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davmillar
Posts: 44
Country : United States |  | | FLIP will take place November 20-21, 2010. When started, you will have 50 minutes to complete FLIP. | FLIP will feature puzzles with a FLIP theme where part of the puzzle must be changed or mirrored by flipping. | | The test will consist of 12 puzzles. There will be a total of 500 points. Samples are available in the information booklet. | Bonus points will be awarded for finishing early, but only if at least 6 puzzles are solved. Full details are in the IB. | | The majority of the puzzles are by me, David Millar. Find more of my puzzle related work on my blog, The Griddle. | Special thanks to Deb Mohanty for creating a puzzle and helping run the entire test, and to Grant Fikes for his help timing out the test. |  If you have a Personal Page on The Griddle, you may unlock the special FLIP Badge. Just go to your profile (or create one if you would like one) and enter the following codes:
FLIP
trib | Thank you all again for giving me the opportunity to host a puzzle test!
Grab the information booklet now! |
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davmillar
Posts: 44
Country : United States | |
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David McNeill
Posts: 63
Country : United Kingdom | In the final puzzle, is the mirror symmetry necessarily about a vertical axis?
Thank you,
David McNeill. |
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davmillar
Posts: 44
Country : United States | Yes, the mirror symmetry in FLIP Every Second Breakpoint must be across the vertical axis. As such, the letters above the grids are mirrored such that both will give the same letter-number pairs when solved properly. |
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vopani
Posts: 739
 
Country : India | vopani posted @ 2010-11-15 11:14 PM In Flip Sequence: "Do not count numbers that read the same forward and backward as flipped"
What does this mean?
In Flip Strip: Can we completely remove a strip? (Not part of any given sum) |
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davmillar
Posts: 44
Country : United States | In FLIP Sequence, if a number is a palindrome, such as 22, 141, 3773, etc, it should not be listed when you list the flipped numbers in your solution, since even if you flip it it stays the same.
In FLIP Strips, you may completely remove a FLIPped strip if you need it necessary, but you shouldn't have to. |
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ronald
Posts: 9
Country : United Kingdom | ronald posted @ 2010-11-16 7:44 AM In the first example, "Flip n Fill Sequence", clue E (72) is flipped (27).
If E is referenced in another clue, say the clue was: E + 2
will the answer be 74 or could it be 29?
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debmohanty
Country : India | ronald - 2010-11-16 7:44 AM
In the first example, "Flip n Fill Sequence", clue E (72) is flipped (27).
If E is referenced in another clue, say the clue was: E + 2
will the answer be 74 or could it be 29?
E has to be on-third of A. So E is fixed at 27.
If there were another clue X = E + 2, X has to be 29. But it could be flipped to be 92 (to make the consecutive string )
In summary, the value of each letter is fixed. Some of them are to be FLIPped to make the consecutive string.
David - correct me if I'm wrong. Also, the example does not use any FLIPed letter as a reference. May be you should consider posting a smaller example where a FLIPped letter is used as a reference for another letter clue. |
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debmohanty
Country : India | davmillar - 2010-11-16 12:21 AM
In FLIP Strips, you may completely remove a FLIPped strip if you need it necessary, but you shouldn't have to.
That is not clear to me. I was under the impression that all strips have to be used.
When you say "you shouldn't have to" do you mean "Puzzles are designed in such a way that all strips are to be used"?
Also, can I flip a strip twice?
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Gotroch
Posts: 83
Country : Czech Republic | Gotroch posted @ 2010-11-16 3:22 PM FLIP 'n' Fill Sequence - Is it allowed to use non-flipped numbers with zero at first place ( 09 ) or we have to use ( 9 )?
(There is 09 in the example, but this number is reversed 90). |
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David McNeill
Posts: 63
Country : United Kingdom | In Shape Sudoku, one of the givens in the upper diagram is incorrect. I guess from the symmetry that the 5 in the bottom row should have been given instead of the 3 in the right-hand column.
David McNeill. |
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davmillar
Posts: 44
Country : United States | @ronald and Deb:
In the FLIP and Fill Sequence, the value of each letter is fixed. That value may need to be entered backwards to create the sequence, but the original value is still fixed. So if E is 27, E + 2 is 29, not 74.
@Deb (and Rohan):
Yes, the puzzle is designed so that all strips must be used in some way. A strip should not be flipped twice.
@Gotroch:
You may use additional zeroes to pad an answer (e.g. 9 becomes 09 or 009)
@David:
I'll fix that immediately - thank you for catching it. The 3 in the right-most column should have been a 1. |
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Para
Posts: 315
Country : The Netherlands | Para posted @ 2010-11-17 5:00 AM Hi
I was a bit confused for a while at K in flip the sequence. I read it as (Square root of J) + 3, except it actually is square root of (J+3). Mathematically my way is correct. Is this intentional to be able to be read 2 ways? If not, i just hope the clues will be unambiguous in the test. Would be kinda annoying to get stuck on something like that. |
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davmillar
Posts: 44
Country : United States | @Para It shouldn't be ambiguous. I'll double check to see if the test has any ambiguous clues like that and fix them immediately, and will update the IB very soon as well. Sorry!
Edit: There was one similar problem in the PB that I found and fixed, and I've sent the revised IB and PB to Deb. Thanks again for the questions and finding these problems!
Edited by davmillar 2010-11-17 5:07 AM
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vopani
Posts: 739
Country : India | vopani posted @ 2010-11-18 12:10 AM Can '0' be used as a perfect square? |
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davmillar
Posts: 44
Country : United States | @Rohan: Yes, it can. |
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Administrator
Country : India | |
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davmillar
Posts: 44
Country : United States | I just want to say thanks again to Deb for facilitating the test and Grant for test solving, and best of luck to everyone who will be taking the test. I hope you all enjoy the puzzles a bunch!
Edited by davmillar 2010-11-20 12:53 AM
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David McNeill
Posts: 63
Country : United Kingdom | Enjoyed the test. Don't know why, but I had trouble entering the solution code for puzzle 7. Please check my answer manually.
David McNeill. |
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Administrator
Country : India | David McNeill - 2010-11-20 7:19 AM
Enjoyed the test. Don't know why, but I had trouble entering the solution code for puzzle 7. Please check my answer manually.
David McNeill. David, It is already marked as correct for you.
Was not expecting that one will enter 13 commas along with 20 digits :- )
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figonometry
Posts: 30
Country : Canada | Nice test, thanks! That went really quickly. I wasn't expecting so much math, but that's just me not paying attention to the IB.
I screwed up my answer to #2, entering the wrong end of the consecutive chain. Is that a minor enough screw-up that it could be overlooked? |
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motris
Posts: 199
Country : United States | motris posted @ 2010-11-20 9:34 AM That went rather fast, but every moment was enjoyable. I particularly liked the mirror puzzles with 0/2/5. Thanks for these puzzles. |
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Administrator
Country : India | Unlike Renban, you can see everyone's total score after you complete the test.
Note that you can refresh the score page only once in 30 minutes. |
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motris
Posts: 199
Country : United States | motris posted @ 2010-11-20 11:03 AM I actually found I could check the score before my clock ran out. This had two bad problems: first I had to wait 30 minutes to actually see my score due to the refresh penalty, but more importantly it seems this is not info someone should have anytime the test is running. So maybe a lock until clock has run out is best?
Edited by motris 2010-11-20 11:04 AM
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Administrator
Country : India | motris - 2010-11-20 11:03 AM
I actually found I could check the score before my clock ran out. This had two bad problems: first I had to wait 30 minutes to actually see my score due to the refresh penalty, but more importantly it seems this is not info someone should have anytime the test is running. So maybe a lock until clock has run out is best?
Disabled the score page completely until this problem is fixed. |
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vopani
Posts: 739
Country : India | vopani posted @ 2010-11-20 11:11 AM Puzzles were good and enjoyable. I liked ESB, Slitherlink and Mirror 0-2-5 the best.
I feel 50 minutes is too short for a test. By the time you get into the groove of solving, before you know its over. And if someone has a problem like a jammed printer (like me), then there's absolutely no time to coverup.
Also, if players finish the test within 50 minutes (or maybe 40 after seeing Thomas's 'rather fast'), then there should have been more puzzles. The concept of FLIP is fantastic and I dont see why there couldn't have been more puzzles.
Did anyone have trouble with the '1's and '7's? or '0's and '9's? or '5's and '6's? I had to strain a bit to solve (especially the sudoku) some of them. The font was a little disturbing, or maybe it was just my sleepy eye :|
@David
The concept of FLIP was brilliant and I would rate it as one of the best concepts of LMI tests after Mastermind Twins. |
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Administrator
Country : India | motris - 2010-11-20 11:03 AM
I actually found I could check the score before my clock ran out. This had two bad problems: first I had to wait 30 minutes to actually see my score due to the refresh penalty, but more importantly it seems this is not info someone should have anytime the test is running. So maybe a lock until clock has run out is best?
Fixed. Thanks for reporting.
The score page was always designed to display score only after the clock has run out.
But with some changes yesterday (especially the 30 minutes penalty which we added to reduce load on server / database ), a 'bug' crept in.
We store all the times (time for submission, time of checking score etc ) in the database. A quick check revealed that no one else had visited the score page before completing.
And you visited 'long time' after you submitted your last answer :- ) |
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rakesh_rai
Posts: 774
Country : India | Rohan Rao - 2010-11-20 11:11 AM
I feel 50 minutes is too short for a test. By the time you get into the groove of solving, before you know its over. And if someone has a problem like a jammed printer (like me), then there's absolutely no time to coverup. I also think 50 minutes is more of a warm up than a test, especially in an online scenario. I think this was one puzzle test where you did not need a printer and the puzzles could be solved equally well online (paint ). The idea of a puzzle test on a 'FLIP' theme is a good one, but it could have perhaps been a 100+ minute test. |
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neerajmehrotra
Posts: 329
Country : India | GUYS 50 MINS IS TOO LESS..
You have to be Thomas to play in such a short time.....
I wasted 10 mins (20% of the total time) as the printer gave way.....
but nevertheless puzzles are nice... enjoyed doing them............. |
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motris
Posts: 199
Country : United States | motris posted @ 2010-11-20 10:41 PM I think you all are being a bit harsh to say that this test is too short and needs more puzzles to be satisfying. I don't think this was a "warm up" at all. And if all authors are required to make 2 hour tests as a prerequisite in the future, you'll likely get fewer tests since writing good puzzles is tough!.
The 12 puzzles in FLIP are a very good set and have a lot of novelty which is refreshing. I guess maybe what you are saying is you would have wanted more because they were good, and with this I certainly agree.
This discussion brings up another point which is that we do set time limits on tests that don't necessarily need to be hard limits. 1h or 75 minutes could also be used on this test, and more solvers get an opportunity to finish, without compromising the quality of the puzzles. I wonder if I should experiment with a whole new scoring format on my next LMI test (many, many months away) where perhaps there isn't a set clock, but instead the value of the puzzles declines with time. So solvers that finish the whole test in 50 minutes will get more points than someone that spreads it out over the weekend and takes 6 hours, but everyone can enjoy the test at their own speed, within the two day window, and if things like printer errors or internet disconnections or phone calls come up, you can still continue the test after the interruption ends (but with a small sacrifice to your score). |
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purifire
Posts: 460
Country : India | @Motris
I couldn't agree more..... :)
Rishi |
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vopani
Posts: 739
Country : India | vopani posted @ 2010-11-20 11:00 PM motris - 2010-11-20 10:41 PM
This discussion brings up another point which is that we do set time limits on tests that don't necessarily need to be hard limits. 1h or 75 minutes could also be used on this test, and more solvers get an opportunity to finish, without compromising the quality of the puzzles. I wonder if I should experiment with a whole new scoring format on my next LMI test (many, many months away) where perhaps there isn't a set clock, but instead the value of the puzzles declines with time. So solvers that finish the whole test in 50 minutes will get more points than someone that spreads it out over the weekend and takes 6 hours, but everyone can enjoy the test at their own speed, within the two day window, and if things like printer errors or internet disconnections or phone calls come up, you can still continue the test after the interruption ends (but with a small sacrifice to your score).
Ours Brun had organised a championship in May last year in which the scoring format reflects what you suggested. I quite liked the idea and it will be interesting to see if someone takes that up.
More about the contest here: http://rohanrao.blogspot.com/2009/05/sudoku-tournament-by-ours-brun... |
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figonometry
Posts: 30
Country : Canada | It would be interesting to do a test with no time limit, because I'm curious how long it would take me to complete this (or any other test, for that matter). It would have to be a shorter test like the FLIP, because I'll never get more than two hours at a time to solve one, (much less the 10 hours it would take me to do something like the USPC). Maybe the points could be based entirely on how quickly someone finishes the test, with demerits based on how many puzzles remain unsolved (or wrong)? Of course then the solver would have to figure out if it's worth more to check for errors or to keep the points.What about having 10 different PDFs, with 10 different passwords, and a week to solve all 10 puzzles? |
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motris
Posts: 199
Country : United States | motris posted @ 2010-11-20 11:16 PM figonometry - 2010-11-20 11:03 PM
What about having 10 different PDFs, with 10 different passwords, and a week to solve all 10 puzzles?
Because of the disparity in printing out paper and such, fragmenting a test into so many pieces may not be such a good idea. But this would be an ideal option for a test that could be solved on an applet. Take a sudoku test that can be solved online; it would be an interesting format to set up 10 "start" buttons for 10 puzzles, so the individual time for each could then be recorded. Maybe scoring is based on finishing puzzles (so time doesn't matter ) and top 20 solvers on each puzzle by time get small amount of bonus. So it is a race for the best solvers, and a slightly more relaxed competition that can be done over a weekend without needing 2 straight hours for everyone else. |
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forcolin
Posts: 172
Country : ITALY | Just to let anyone know that a Sudoku contest based on this very principle is currently running on argio-logic.net at this address [url]http://www.argio-logic.net/?p=headshrinker[/url]
the contest is based on "tough" diagrams (er, at least for me...) and the time starts ticking when a player opens an applet (take care not to open two or more applets at the same time...)
if you want to have a try.....
Stefano
Edited by forcolin 2010-11-21 12:06 AM
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purifire
Posts: 460
Country : India | Great puzzles David.... It was real fun attempting these.... looking more of such puzzles to keep me interested :D
0-2-5 and the mirrors were great fun.... |
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detuned
Posts: 152
Country : United Kingdom | detuned posted @ 2010-11-21 2:10 AM Thanks David - short and sweet - and definitely well executed. And not forgetting Deb on the ESB too - an entertaining puzzle! |
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forcolin
Posts: 172
Country : ITALY | david and deb
I typed the results for the puzzle 4 BOTH BOTTOM LINES instead of as marked (last second rush) - I wonder if I can be awarded the points for that puzzle
by the way all diagrams (at least all those I solved) were very exciting - and I like this sort of "blitz" contests. easier to find an hour in a (usually) busy weekend rather than 2.5 hours
Stefano
Edited by forcolin 2010-11-21 3:51 AM
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debmohanty
Country : India | forcolin - 2010-11-21 3:42 AM
I typed the results for the puzzle 4 BOTH BOTTOM LINES instead of as marked (last second rush) - I wonder if I can be awarded the points for that puzzle
Stefano Yes, awarded. It is taking little more time to check the claims this time because of unstable internet connections, but all the claims will be checked before the final results.
That brings me to the very interesting discussion motris has started.
1 ) Given a set - e.g. Decathlon - how much time should the test run so that everyone can enjoy the puzzles?
It is likely that many players don't get to solve the puzzles once the test is over. And also there is some incentive for solving the puzzle after the 'official' time.
It will be very interesting to have the points reduce with time. I think Gotroch had proposed something similar earlier.
2 ) The other issue is players not finding enough time at a stretch.
This is a problem for most especially given that there are so many internet competitions these days, and all of them offer something different.
Splitting into 10 sets is rather difficult to manage, but what about splitting into 2 sets each of one hour?
Those who find it difficult to get 2 hours at a stretch, may take the tests in 2 parts.
Players who needs some warm up can take the full test at a stretch.
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purifire
Posts: 460
Country : India | forcolin - 2010-11-21 12:00 AM
Just to let anyone know that a Sudoku contest based on this very principle is currently running on argio-logic.net at this address [url]http://www.argio-logic.net/?p=headshrinker[/url]
the contest is based on "tough" diagrams (er, at least for me...) and the time starts ticking when a player opens an applet (take care not to open two or more applets at the same time...)
if you want to have a try.....
Stefano
Hi Stefano,
yes that is exactly the kind of contest that is being proposed with no time limit.... the best part is there are 3 Indians in the top 4 positions with a canadian participant at 3rd, Cant remember when that happened last time :D
The position might change as the competition is still on and somebody could always solve it faster. 
Rishi |
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debmohanty
Country : India | purifire - 2010-11-21 8:14 AM
yes that is exactly the kind of contest that is being proposed with no time limit I'm not sure what you mean by "exactly that kind". I thought Headshrinkers is about (very- )hard Sudokus, and that is why the contest has no time-limit.
The purpose is completely different here. |
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purifire
Posts: 460
Country : India | debmohanty - 2010-11-21 8:24 AM
purifire - 2010-11-21 8:14 AM
yes that is exactly the kind of contest that is being proposed with no time limit I'm not sure what you mean by "exactly that kind". I thought Headshrinkers is about (very- )hard Sudokus, and that is why the contest has no time-limit.
The purpose is completely different here.
When I say exactly that kind of contest I mean a contest with no time limit... I am not referring to the difficulty level of the puzzles....
The discussion here is about a competition which does not have a time limit. However this type of contest is possible only in an online format ... unless a separate pdf is created for individual puzzles and time for each puzzle calculated when the pwd for individual puzzle is taken from the site.
Rishi |
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SrikanthB
Posts: 5
Country : India | Very nice set of puzzles, David!
It was nice solving some JUST ARITHMETIC puzzles (Sequences, Strips), instead of the regular GRID-based logic puzzles
Also, for a change, the timing was nice - short and sweet (though i could solve hardly few of them)
Edited by SrikanthB 2010-11-21 11:56 AM
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keshava.hs
Posts: 10
Country : India | Hi David,
Amazing set of puzzles!
Thanks a ton for making my week-end thrilling.
Flip n Sequence & 0-2-5 Mirror was great!
3 Cheers,
Keshav
Edited by keshava.hs 2010-11-21 12:12 PM
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akash.doulani
Posts: 157
Country : India | while submitting the answer for flip shape sudoku , we were asked to submit the answer for the 7th row of the first sudoku, but there was also no. 4 marked in an arrow on the left side of the first sudoku. so i thought we had to type row 4 for the answer. so i got it wrong. it will be very kind of the administrators to look into the matter and if possible consider row 4 as my answer and if correct , grant me points for that.......... akash |
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Administrator
Country : India | akash.doulani - 2010-11-21 5:26 PM
while submitting the answer for flip shape sudoku , we were asked to submit the answer for the 7th row of the first sudoku, but there was also no. 4 marked in an arrow on the left side of the first sudoku. so i thought we had to type row 4 for the answer. so i got it wrong. it will be very kind of the administrators to look into the matter and if possible consider row 4 as my answer and if correct , grant me points for that.......... akash
Done
Hope you liked the puzzles. |
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Gotroch
Posts: 83
Country : Czech Republic | Gotroch posted @ 2010-11-21 6:10 PM Administrator - 2010-11-21 5:34 PM
akash.doulani - 2010-11-21 5:26 PM
while submitting the answer for flip shape sudoku , we were asked to submit the answer for the 7th row of the first sudoku, but there was also no. 4 marked in an arrow on the left side of the first sudoku. so i thought we had to type row 4 for the answer. so i got it wrong. it will be very kind of the administrators to look into the matter and if possible consider row 4 as my answer and if correct , grant me points for that.......... akash
Done
Hope you liked the puzzles.
Same thing Akash mentioned, happened to me. Could you please grant me points too. |
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Administrator
Country : India | Gotroch - 2010-11-21 6:10 PM
Same thing Akash mentioned, happened to me. Could you please grant me points too. Done |
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PuzzleScot
Posts: 31
Country : United Kingdom | I entered the wrong key for #4 - I put in the contents of the greyed area rather than the arrowed rows. Any chance of upgrading my score from 'disastrous' to just 'miserable' ?
Nice puzzles - not enough time for me. Will enjoy them later... Thank-you for the contest! |
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debmohanty
Country : India | PuzzleScot - 2010-11-21 11:04 PM
I entered the wrong key for #4 - I put in the contents of the greyed area rather than the arrowed rows. Any chance of upgrading my score from 'disastrous' to just 'miserable' ?
Done |
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willwc
Posts: 12
Country : United States | willwc posted @ 2010-11-22 1:39 AM If someone could check my entry for #1, it would be appreciated. I can't really explain it here without giving away part of the solution, but I think the error there should be fairly clear to someone who looks at it. (Unfortunately, the other 0's I submitted are all legitimately incorrect solutions  )
Thanks to David for the interesting puzzle set, and especially to everyone affiliated with LMI who contributes to administering these contests every month. |
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drsteve
Posts: 12
Country : United Kingdom | drsteve posted @ 2010-11-22 1:44 AM David and Deb
Great test, lots of fun, although as a Maths teacher, I could have done with less adding up.
Time seemed fine to me - I wouldn't expect to finish one of these (and I didn't, obviously) - maybe 60 minutes would have been better, but I still wouldn't have caught the thing that caused me to waste a lot of time on one puzzle (won't say what for fear of spoilers)
Cheers
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rodders
Posts: 4
Country : United Kingdom | rodders posted @ 2010-11-22 2:25 AM Very enjoyable set of tests.
I realise I have entered the incorrect key for #4. I entered the bottom row of both puzzles rather than the 3rd row of the right hand puzzle. I'm relatively confident I have the correct solution, although of course won't give it away here. Any chance of rescuing some points for that puzzle??? |
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radekivv
Posts: 13
Country : United States | Would it be possible to check my answer to #7? I separated lines by commas and the system did not like it. Thanks. |
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radekivv
Posts: 13
Country : United States | Dave, thanks for a very nice set of puzzles! I will definitely finish the remaining ones not to miss any fun :-). |
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davep
Posts: 43
Country : United States | davep posted @ 2010-11-22 3:23 AM Hi Deb -
I also entered the yellow-outlined areas on #4 as my answers ....
In any case, compliments to David for some very clever puzzles (I ran out of time, so I will enjoy Deb's ESB later ).
Best regards
Dave Edited by davep 2010-11-22 3:24 AM
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ostroffj
Posts: 10
Country : United States | Aw, I had my first typo when entering one of the FLIP 'n' Fills. And it knocked me down a bonus point bracket!
If it helps, my typo implies that a number ending in a 0 was flipped (which is clearly false). But I can understand being strict about this, and it's not like I'm really in contention for a top score anyway. |
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detuned
Posts: 152
Country : United Kingdom | detuned posted @ 2010-11-22 7:31 AM Deb - I think there's a bug with regards to the puzzle rating system. I can't seem to give a rating for the two puzzles I had a manual override on the score.
For what it's worth, I thought #3 was a 6/10 and #12 was an 8/10. |
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debmohanty
Country : India | detuned - 2010-11-22 7:31 AM
Deb - I think there's a bug with regards to the puzzle rating system. I can't seem to give a rating for the two puzzles I had a manual override on the score.
For what it's worth, I thought #3 was a 6/10 and #12 was an 8/10. Will have a look before next test. For now, I've added your ratings for the two specified puzzles. |
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Administrator
Country : India | willwc - 2010-11-22 1:39 AM
If someone could check my entry for #1, it would be appreciated. I can't really explain it here without giving away part of the solution, but I think the error there should be fairly clear to someone who looks at it. (Unfortunately, the other 0's I submitted are all legitimately incorrect solutions ) Correct answer 2FGHJ. Your answer 2FGHI.
Marked correct.
rodders - 2010-11-22 2:25 AM
I realise I have entered the incorrect key for #4. I entered the bottom row of both puzzles rather than the 3rd row of the right hand puzzle. I'm relatively confident I have the correct solution, although of course won't give it away here. Any chance of rescuing some points for that puzzle??? davep - 2010-11-22 3:23 AM
I also entered the yellow-outlined areas on #4 as my answers .... Done
Many players did this. Given points to both you and others
radekivv - 2010-11-22 2:46 AM
Would it be possible to check my answer to #7? I separated lines by commas and the system did not like it. Thanks. Many players did this. Given points to you and all others (even who didn't claim ).
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Administrator
Country : India | Checked all submissions for manual overrides. There is none as far as I can see.
Results are frozen now.
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ostroffj
Posts: 10
Country : United States | Admin, I think willwc's point is that there is no row I: the rows read ABCDEFGHJK. So by "I" he meant "the thing after H". |
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Administrator
Country : India | Congratulations to Thomas Snyder and Hideaki Jo for topping in FLIP. Only 2 players to complete, and by what a margin - 18 minutes remaining. Only few seconds separating them apart.
Nikola continued his trend of single-puzzle-mistake from Renban. He would have otherwise got 9 minutes bonus.
In Indian ladder, Rakesh converted his 'good performance in Renban' into a 'great performance in FLIP'. And we've Keshava at 3rd position among Indian participants. Well done, Keshava and hope to see you do better in upcoming tests.
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Administrator
Country : India | ostroffj - 2010-11-22 8:54 AM
Admin, I think willwc's point is that there is no row I: the rows read ABCDEFGHJK. So by "I" he meant "the thing after H".
That was careless from me. Sorry willwc. Thanks ostroffj for pointing.
3 players did the same mistake.
pushpa.mr
RJH0723
willwc
All of them get full points.
willwc's score is 360 now, and he moves to 15th position. |
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Administrator
Country : India | Slightly lesser participants compared to the last two LMI tests.
98 out of 115 players got non-zero scores. Thank you everyone for participating.
Those who could not participate should try to solve and enjoy the puzzles at leisure. |
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Administrator
Country : India | |
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ostroffj
Posts: 10
Country : United States | All of them get full points.
And I don't suppose I could get credit for #3? It was the same kind of mistake, though less clear cut: instead of "K" I wrote "J", which unfortunately is an actual row. But then, if the last row ends in a 1, then I couldn't have thought J was flipped, or else that answer would be a two-digit number starting with a zero. |
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davmillar
Posts: 44
Country : United States | Thank you to everyone who participated in the test and for the feedback afterward.
I'm sorry that the test was so short. Given the number of other tests going on this past weekend as well as over the last couple of weeks and upcoming weeks, I thought that a shorter, simpler test would be appreciated. I also hoped a shorter test would inspire more people to give the test a try.
I'm glad to see that many of the puzzles were well-liked. From what I can gather, the FLIP Mirror 0-2-5 were among the favorites, so perhaps I'll make more of those to put on The Griddle when I have some spare time.
Thanks again to all!
David |
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davmillar
Posts: 44
Country : United States | @ostroffj: In the other cases, it was clear that the answer was incorrectly entered since no row called 'I' exists. In your answer, since a row called 'J' exists, it would be unfair to give credit since it was not clear if that was your intended answer or if it was a typo. It is not a personal decision, but to be fair we cannot award you those points.
In any of my future tests with LMI, I will be sure to very clearly label rows as needed, and will only accept the correct answer as indicated by the Instruction Booklet to ensure that the scores given to all are fair. |
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figonometry
Posts: 30
Country : Canada | I very much appreciated that the test was short. I'm far more able to do an hour-long test. I mean, I can now finish it while my wife is watching some TV show I don't like! |
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zhergan
Posts: 32
Country : Turkey | zhergan posted @ 2010-11-23 12:05 AM  David and LMI team for conducting such a nice contest  I enjoyed the puzzles which involved math a lot. I liked the fences puzzle a lot also. I must say it is a very well designed one. Even I did not try to solve the ESB during the test I must also say that it is a good constructed one. Actually I usually make some errors while solving such puzzles in a short time. These are not my type I think. But I enjoyed solving this one after the test. Conrats to all toppers and every participant.
Regards,
Zafer Edited by zhergan 2010-11-23 12:06 AM
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ostroffj
Posts: 10
Country : United States | I was also a fan of the test's length, even though it certainly flew by. I didn't learn about the test until Sunday morning, and only had about 90 minutes of consecutive free time in which to participate, so much longer and I would've been right out. |
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rakesh_rai
Posts: 774
Country : India | I was just looking at the results. One surprising observation was regarding FLIP Strips.
It seemed a very easy puzzle to me. Just add the numbers on the left - you get 90. And when you add the strips, you get 91. So it is very clear that a 1 has to go. After that it is trivial. But this was attempted by the fewest number of participants - even less than the two 65-pointers !! |
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davmillar
Posts: 44
Country : United States | rakesh_rai - 2010-11-24 1:42 PM
I was just looking at the results. One surprising observation was regarding FLIP Strips.
It seemed a very easy puzzle to me. Just add the numbers on the left - you get 90. And when you add the strips, you get 91. So it is very clear that a 1 has to go. After that it is trivial. But this was attempted by the fewest number of participants - even less than the two 65-pointers !!
This was one of the two outcomes I expected. I thought either it would be found as too easy or as too difficult depending on if a particular solver figured out the trick or not. Between FLIP Strips and FLIP 'n' Fill Sequence, I think those puzzles were good challenges for me to make something non-grid-based (and possibly good to make more for posting on The Griddle ), but would be bad in a competition setting since everyone is used to not doing so much math.
(Random side thought though, I was thinking of releasing a special edition combined IB/PB with added notes/commentary, answer keys for the test puzzles, and possibly extra puzzles in the types most well-liked by test-takers. Would anyone be interested in something like this, or would it be a waste of time?) |
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debmohanty
Country : India | davmillar - 2010-11-23 10:53 PM
(Random side thought though, I was thinking of releasing a special edition combined IB/PB with added notes/commentary, answer keys for the test puzzles, and possibly extra puzzles in the types most well-liked by test-takers. Would anyone be interested in something like this, or would it be a waste of time?)
David, I think thats a good idea. We never had thought abt having anything like that for any test.
You can also include some general stats from the score page.
Of course, many players would be interested in the extra puzzles :- )
Looking forward to your special edition! |
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detuned
Posts: 152
Country : United Kingdom | detuned posted @ 2010-11-24 2:40 AM rakesh_rai - 2010-11-23 5:42 PM
I was just looking at the results. One surprising observation was regarding FLIP Strips.
It seemed a very easy puzzle to me. Just add the numbers on the left - you get 90. And when you add the strips, you get 91. So it is very clear that a 1 has to go. After that it is trivial. But this was attempted by the fewest number of participants - even less than the two 65-pointers !!
It wasn't quite trivial. There were two possibilities that gave very similar looking equations (the sums were related by a single transposition ), and I happened to pick the wrong one, initially thinking it was good. |
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motris
Posts: 199
Country : United States | motris posted @ 2010-11-24 3:17 AM detuned - 2010-11-24 2:40 AM
rakesh_rai - 2010-11-23 5:42 PM
I was just looking at the results. One surprising observation was regarding FLIP Strips.
It seemed a very easy puzzle to me. Just add the numbers on the left - you get 90. And when you add the strips, you get 91. So it is very clear that a 1 has to go. After that it is trivial. But this was attempted by the fewest number of participants - even less than the two 65-pointers !!
It wasn't quite trivial. There were two possibilities that gave very similar looking equations (the sums were related by a single transposition ), and I happened to pick the wrong one, initially thinking it was good.
There were several puzzles on this test with some obvious tricks if you had planned ahead. Flip Strips fits that category, but the thing is while its clear you can use the total addition to know how much is "missing" in the solution, what you don't know until doing all the addition is that the result here is 90 and 91 making the puzzle very easy. Since it probably takes a half minute to know if the puzzle is very easy or somewhat hard, I'm guessing many solvers went to other places.
I personally found the Slitherlink to be the one that was most trivial if you had thought about how the gimmick would work. Certainly there will be one of two mirror axes unless it's an odd sized grid, with no line segments on that axis since it must form a loop. This means 3's can't touch that axis, which lets you exclude the vertical option rather quickly. Then you just copy the top numbers into the bottom and solve half a slitherlink, doubling the count for the answer entry. Hardly worth 65 points, if you planned ahead. The other 65 pointer was much harder. |
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rakesh_rai
Posts: 774
Country : India | motris - 2010-11-24 3:17 AM
I personally found the Slitherlink to be the one that was most trivial if you had thought about how the gimmick would work. Certainly there will be one of two mirror axes unless it's an odd sized grid, with no line segments on that axis since it must form a loop. This means 3's can't touch that axis, which lets you exclude the vertical option rather quickly. Then you just copy the top numbers into the bottom and solve half a slitherlink, doubling the count for the answer entry. Hardly worth 65 points, if you planned ahead. The other 65 pointer was much harder. That was a neat little trick...to solve half a slitherlink...I spent quite a lot of time on this, solving the full slitherlink the hard way. |
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rakesh_rai
Posts: 774
Country : India | Another thing that I am not fully able to understand is the (partial) bonus system.
Taking FLIP as an example, if X solved 9 puzzles in 40 minutes (but failed to solve the 10th one), he gets 4X10=40 bonus points. On the other hand, Y, who solved 9 identical puzzles in 39 minutes and ended up solving the 10th one (worth 35 points) in the nick of time, gets zero bonus points.
The main doubt that I have is whether we should use the last correct answer submission time OR the 6th/9th correct answer submission time as the reference point. Y was actually faster to 9 puzzles. But X got 40 bonus points for a failure while Y got 35 puzzle points for a success. |
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debmohanty
Country : India | Rakesh - thanks for bringing it up again (when it seemed to me that you have gained few ranks in FLIP because of the partial bonus system :-)
The bonus system works well when we assume that a player submits as soon as they solve a puzzle. That is an incorrect assumption, and definitely not true in case of puzzle tests.
May be some members will have other solutions to the partial bonus system. It will be nice to discuss something and finalize before the next test. |
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rakesh_rai
Posts: 774
Country : India | debmohanty - 2010-11-24 5:55 PM
Rakesh - thanks for bringing it up again (when it seemed to me that you have gained few ranks in FLIP because of the partial bonus system :-) Exactly Deb. My case is similar to X (9 puzzles, 12 bonus points ), and Y solved 10 puzzles but got ranked below me (0 bonus points ). |
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motris
Posts: 199
Country : United States | motris posted @ 2010-11-25 8:00 AM I'm not necessarily sure of the right implementation to fix the bonus problem. Here, I was "done" with the test with 21 minutes left on the clock, started to check my solutions, found my typo in the first mirror puzzle (I typed a 6 instead of an 8 so had two 6s in the string), had my next "done" time at 18 minutes and something on the clock, continued checking. Then checked some more. Didn't change any more solutions, so the 18 minute time lasted. In a live event, with that much time bonus (25% of round value) at stake, I would have done a first pass at checking as above and turned in my paper with 16 minutes on the clock, for less bonus than this test gave me. But that is the difference between online and live. Here there is no "done" button that absolutely ends the test. And I'm not sure there should be. But, playing devil's advocate, if there were such a button, then no one would be earning bonus if they were still trying to solve, and you could separate the cases of someone who made a typo but finished very fast from someone who was still solving but got stuck on one puzzle.
What is dissatisfying here as in rakesh's example, as was true with my Decathlon structure with "friendly" bonuses for completion, is the situation where someone submitting another answer could lead to them losing points and the main motivation should always be to solve more puzzles and not think about these meta-effects of bonus. The simplest system is therefore to not use time bonus at all, but accept raw times of last correct submission (ie when a solver reaches a score) as the tie-breaker. With that system, no one will ever stop solving to collect more partial time bonus. It doesn't deal with the solver finishing 30 minutes early with a mistake problem - which is what started the time bonus discussion here on Broken Pieces I think, if not from earlier Mock Tests in Sudoku - but perhaps the system should be triggered solely by that situation - 100% correct, or just 1 wrong. Because I think most of us are just trying to solve as much as we can, whether we catch our mistakes or not, and more complicated systems simply confuse a ranking in the ways we've run into in the last few tests.
Edited by motris 2010-11-25 8:02 AM
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debmohanty
Country : India | Yes, the partial bonus system triggered after Broken Pieces. Until that point bonuses were given if all puzzles were 100% correct, even during Sudoku Mock tests.
The primary intention was to handle cases where player has submitted all puzzles well ahead of time, but has a submission mistake (like yours in Broken Pieces)
With the recent friendlier bonus systems having undesired side effects, we probably just need to think about how to identify and give benefit to early-completions-with-submission-mistakes.
We should probably give partial bonus points if <= 10% puzzles are incorrectly submitted.
The major flaw in the current system is that it does not differentiate between "incorrect submissions" vs "no submission" vs "random guesses".
Authors and organizers should be allowed to judge what is an "incorrect submission", and what is not. This has to be a manual check. Given that only the top solvers are expected to get bonus, it will be fair to assume that they won't make "random guesses" just to get time bonus. So it really might boil down to differentiating between "incorrect submissions" vs "no submissions"
Partial bonus should be given only if the wrong answer is judged as "incorrect submissions".
No partial bonus in case of "no submissions".
No partial bonus if more than 10% of puzzles are incorrectly submitted, irrespective of how minor the mistake is.
Also, the difference between bonus points per minute in case of all correct and 90%correct should be substantial.
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debmohanty
Country : India | Adding a "Done" or "Claim Bonus" button (the equivalent of "Raising hand" in an offline event ) should be fairly easy to implement from technical point of view. The "Done" button should be enabled after all puzzle answers are filled. Once the player clicks on "Done", the submission button should be disabled. The time bonus, if any, will be computed from when the player clicked on "Done".
Just like you, I'm not entirely sure, if we should have this feature. It probably adds one more overhead for players. As such players forget to click on Submit and have suggested to remove the Submit button.
Adding a "Done" button will probably complicate it further, although I believe it is something good to have.
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motris
Posts: 199
Country : United States | motris posted @ 2010-11-25 9:59 AM debmohanty - 2010-11-25 9:35 AM
Authors and organizers should be allowed to judge what is an "incorrect submission", and what is not. This has to be a manual check. Given that only the top solvers are expected to get bonus, it will be fair to assume that they won't make "random guesses" just to get time bonus. So it really might boil down to differentiating between "incorrect submissions" vs "no submissions"
This is a very good point. When watching submissions come in for Decathlon I remember one solver in the top ranks had a typo in a skyscrapers puzzle and finished with a fair bit of time but only 29 correct. He eventually corrected the mistake losing about 2-3 minutes to get to 30 correct (which had, due to the time bonus problem, a net neutral effect on his score unfortunately ), but it would be obvious if he had not made the fix that this was an incorrect submission. It wouldn't necessarily get points, but it wouldn't be thrown out in a "this solver did not try the puzzle" sense if time bonus required an incorrect submission. The challenge then is having a good answer submission that can tell you if this is enough progress. A full row or two rows on a sudoku is certainly a good condition to attempt this test. The number of tents on a diagonal in a tents puzzle may not be. But it would be good to try this alternative going forward. Edited by motris 2010-11-25 10:00 AM
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debmohanty
Country : India | I agree having a good answer key is critical for this aspect.
But even otherwise having a non-guessable and non-error-prone answer key is still required for all puzzles tests, irrespective of whether it is used for 'partial bonus' system or not.
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davmillar
Posts: 44
Country : United States | | FLIP Special Booklet contains the instruction booklet and puzzle booklet from FLIP along with a bunch of extra content. | | Author notes and comments. | Bonus unused puzzles. | | Test facts and figures. | Brand new bonus puzzles. | | Neat purple design. | Full answer key. | Thank you all once more for giving me the opportunity to host a puzzle test and for participating!
Grab the special booklet now! |
Click here for SPECIAL BOOKLET!Edited by davmillar 2010-11-26 11:27 AM
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debmohanty
Country : India |
David, Thanks for the Special Booklet.
I'm yet to solve any of the extra puzzles, but I love your comments and notes.
Appreciate your efforts!
Deb
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LMI November Puzzle Test - FLIP