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Logic Masters India announces April Puzzle Test — Twist

Author : Deb Mohanty

Date : 09^th and 10^th April

Length : 90+10+10+10 minutes

IB and Submission Link : Here

Puzzle Types : Minor rule changes to 12 common types of puzzles.

I can see a lot of timing strategies in people's minds.

Nice and interesting IB......

A Small Query on reduction in points.........
Will the points will be reduced for all the puzzles submitted, even if I submit only one puzzle after 90 mins, or only the points of the puzzles submitted after 90 mins will be reduced.

neerajmehrotra - 2011-04-02 1:57 PM

A Small Query on reduction in points.........
Will the points will be reduced for all the puzzles submitted, even if I submit only one puzzle after 90 mins, or only the points of the puzzles submitted after 90 mins will be reduced.

Puzzles submitted within 90 mins will always get 100% value, irrespective of what you do in remaining 30 minutes.
Puzzles submitted within 90-100 mins will always get 75% value, irrespective of all other submissions you make.
...

Hope it is clear.

Thanks, Its crystal clear.............

Interesting puzzles Deb!

Looking forward to participate in this competition after a long gap.

Hi,

Can you please confirm the times, with time zone, that this contest is available for competing?
Note that the UK is currently in British Summer Time (GMT+1)

Thanks
Alan

Edited by PuzzleScot 2011-04-05 3:41 AM

PuzzleScot - 2011-04-05 3:40 AM

Hi,

Can you please confirm the times, with time zone, that this contest is available for competing?
Note that the UK is currently in British Summer Time (GMT+1)

Thanks
Alan

Done. Please check the submission page.

"twist" IB seems to be very interesting. will miss the test this time owing to travel. will take it offline.

Note about Hitori Sum Answer key

This is only puzzle where answer is 'by column'. This is not easy to remember while entering the solution under time-limit.
So I decided to mark all the columns as shown below.

There is no change in rules or answer key definition.

Just to make sure that everyone understands the point reduction formula, here is an example.
Basically, 'how much you get for a particular puzzle' depends upon 'when you submitted it'. Nothing else.

In the answer for the Minesweeper puzzle, there is a mine next to the 4 (left end of second row) that has 3 mines around it. Is this allowed?

You are referring to R2C1. Yes, that is allowed.

The following situation is NOT allowed because of R2C3.

Cells with numbers will have exactly same number of mines around them.
Cells with mines may have any number of mines around them

Cells without numbers and mines can NOT have 3 mines around them. [This is the only rule change wrt a standard Minesweeper puzzle ]

Ah thank you. I thought it meant:
(Cells without numbers) and mines can NOT have 3 mines around them
instead of:
Cells without (numbers and mines) can NOT have 3 mines around them

Looking forward to trying these twists. The hitori sum is my favourite new idea, normally the numbers just get ignored.

During IB review itself, we found that the wording is little cryptic. So I included the example such that all the scenarios are reflected.

Hope it is clear to all.

Ah, glad this was addressed, I just logged on to check on the same thing, and I had misinterpretted the instructions the same way. Thanks.
I look forward to this one. Thanks again to the organizers and creators!

Puzzle Booklet uploaded. It has 12 pages, each page has 2 puzzles (and instructions and solution to the example) of one particular type.
There is no cover page.

Twist has started.
Good luck everyone!

Wow! Phenomenal test with a nice balance of difficulties and many fun puzzles on both ends of the spectrum. The twists were very interesting, and you even managed to make Hitori fun! You don't know how much that means to me. Thanks a lot Deb.

The score page doesn't show the bonus properly. Will be uploading fixed score page in few minutes

debmohanty - 2011-04-09 10:50 AM

The score page doesn't show the bonus properly. Will be uploading fixed score page in few minutes

Bonus should show up properly now - here is the link to score page - http://logicmastersindia.com/M201104P/score.asp - which you can view after you complete the test.

A twisted view of the score page available here - http://logicmastersindia.com/M201104P/score.asp?view=twist

motris - 2011-04-09 10:45 AM

Wow! Phenomenal test with a nice balance of difficulties and many fun puzzles on both ends of the spectrum. The twists were very interesting, and you even managed to make Hitori fun! You don't know how much that means to me. Thanks a lot Deb.

Thanks a lot for the feedback.
Yes, Hitori is a type that is not liked by all. I'm glad that the 2 Hitoris came out well and you liked them.

Thanks for the test. I had fun. My favourite was the ABC twist, really good puzzles both. And I managed to avoid making any entry errors, although I did take a very cautious approach entering my answer keys this time, probably cost me some time as I doublechecked what I had put in each time.

thats a nice clarification.before looking at this post,i was surprised about the reduction as i thought it was calculated on the total score.This logic i think should be posted on the contest page too,to ensure no one is in doubt.

anurag - 2011-04-09 1:26 PM

thats a nice clarification.before looking at this post,i was surprised about the reduction as i thought it was calculated on the total score.This logic i think should be posted on the contest page too,to ensure no one is in doubt.

We've experimented with many bonus systems, not all of them are flawless - but we'll never have a bonus system where players need calculators (more than pencil and eraser) before submitting a puzzle.

that sounded funny.i didnt say the contestants would start calculating.in fact i liked this penalty(bonus)system:) Good and simple one.
To make it better,why not increase the number of intervals and make it 6 ,of 5 mins each.That can probably sharpen the evaluation.

anurag - 2011-04-09 1:46 PM

that sounded funny.i didnt say the contestants would start calculating.in fact i liked this penalty(bonus)system:) Good and simple one.
To make it better,why not increase the number of intervals and make it 6 ,of 5 mins each.That can probably sharpen the evaluation.

Changing the interval to 5 minutes is an option. But it might become too stressful for players in last 30 minutes.
As the poll options indicate, we definitely can make adjustments to this system in future.

Nice twists. I liked L&M&I, Lights and Hitori Sum the most.

a question off the topic..I want to know if the preliminary online is all we need to give(as it used to be every year) ,or the regional rounds are required too?

Odd skyscraper: Some evens inside look like valid skyscrapers .The 2,4 in the third row can be valid and satsify the outside '3' at the same time.Is that a problem with the example? or will that hold for the test puzzle too?

Edited by anurag 2011-04-09 5:30 PM

anurag - 2011-04-09 5:25 PM

Odd skyscraper: Some evens inside look like valid skyscrapers .The 2,4 in the third row can be valid and satsify the outside '3' at the same time.Is that a problem with the example? or will that hold for the test puzzle too?

I think the rule and the example match perfectly.

I don't understand why people like the reducing points. It's quirky and fun, but does it make the contest better?
As a middle-of-the-field solver, it doesn't change my strategy at all - I've always started with the puzzles that get me the fastest points, and leave the hard/slow ones for last. I assumed most people did this (unless they're intending to just do all the puzzles!).
If we scored this test normally, then wouldn't the rankings be almost exactly the same order anyway? e.g. we're all penalized a similar percentage of our total score in the end, except the fastest solvers who get an increased lead now.

And on a different topic, the puzzles were great and I enjoyed the test. Thanks Deb!

My own reason for liking it is that I think it's a much better tiebreaker than simple time bonus systems for sorting out the top of the rankings. For instance, awhile ago there was a test in which motris finished ahead of uvo by a single second. There might have been a clearer victor with a scoring system like this.

Speaking as someone who normally tries to solve all puzzles and doesn't prioritize order, with the occasional consequences, on this test I certainly prioritized order much more. If anything, the slight change I might imagine solvers taking is shifting earlier to "clean-up" solving time versus going after big fish. With 15 minutes left to 90 minutes, you are less likely to start a 60 pointer versus smaller puzzles.

One of the goals of the delayed scoring I think is to run shorter tests for longer times without necessarily compromising the results at the top. FLIP is a great example of this type of test. While this test has a lot of easy puzzles, it probably is still too long of a test to showcase the best benefits of this type of system, which would be a 40-60 minute for uvo test that gets run for 2 hours (or more) instead.

To build off Melon's comment, I'm not sure this system can ever better separate the virtual tie between Ulrich and myself when we are 1 second apart and completely correct, but diminished scoring can help when a solver stops solving (with something like an error) but is at 23/24 very early, versus 24/24 after much more time. The clearest example was unfortunate for me but on Broken Pieces where I was done first (several minutes ahead of others, 45 minutes before end of the test) but with an entry error that I never caught. I ended up 12th, but some (hopefully not just me) would say my rate of solving was fast enough that my small mistake equaling no time-bonus was not a big enough mistake to cost the amount of points it did. Broken Pieces was an easy test with about 2x the amount of time needed, and is maybe even a better test than FLIP to showcase where this scoring could improve rankings.

Edited by motris 2011-04-10 12:18 PM

kiwijam - 2011-04-10 10:40 AM

...If we scored this test normally, then wouldn't the rankings be almost exactly the same order anyway? e.g. we're all penalized a similar percentage of our total score in the end, except the fastest solvers who get an increased lead now.

I think 80-90% of rankings would not change much, whatever system you use. So, that may not be the best reason for not liking a particular system.

If the basic assumption for this system is that "top solvers should be able to finish the test within the first time slab (90 minutes, here)" then I do not understand how this system will help better define the rankings at the top (as they all are expected to finish within 90 minutes and rank according to their finish times anyway).

On the other hand, this system will further tend to increase the difference between top solvers and others. Top solvers will get (699 PLUS bonus) but others will be penalized and they may get about 70-90% of their score based on when and what they submitted. Compared to previous systems, there is no change in top solvers' score but others' scores is lesser. If this is what is desired, then, yes, this system indeed serves its purpose. But I am not sure that is what is desired.

Maybe, it can work better in easier tests.

Excellent puzzles. excellent presentation.
Once again I fell victim to the answer format - miscounted arrows, miscounted cells... not a good feeling.
Asides that, the new time format does raise some debates.
It's interesting, but I hate how prioritizing solving order suddenly becomes crucial.
What if this system is used on a test where the puzzles are all roughly the same level?
Then this would ultimately test solving speed as opposed to how well you plan your solving order.

Hi anyone

I am on holiday in Poland and have must managed to get a computer at 9:50pm on the Sunday evening, but I cannot find a start test on the TWIST page. Please can somebody put the password into this forum so that I can access the questions. I will email people in the UK my results at midnight. Thank you.

Ken

Janix - 2011-04-11 1:28 AM

Hi anyone

I am on holiday in Poland and have must managed to get a computer at 9:50pm on the Sunday evening, but I cannot find a start test on the TWIST page. Please can somebody put the password into this forum so that I can access the questions. I will email people in the UK my results at midnight. Thank you.

Ken

I think Deb is not here just now. I answer:

"I cannot find a start test on the TWIST page"

On the twist page, you must login before start. When you are logged, you'll see a big "start" button.

Fred

Very nice and fun test! Bravo, Deb!

Regarding the previous discussion, I think it's time to stop experimenting with bonus systems and try to establish criteria that would apply to all future tests. For such single and one-time events, the first view, of course, should be the score, and then the solving time. I think it's very enough.

Nikola

Arrgh

I am working on a very old laptop and I have just discovered a very small button half way down a blank page and I have started.

Thanks Fred

kiwijam - 2011-04-10 10:40 AM

I don't understand why people like the reducing points. It's quirky and fun, but does it make the contest better?
As a middle-of-the-field solver, it doesn't change my strategy at all - I've always started with the puzzles that get me the fastest points, and leave the hard/slow ones for last. I assumed most people did this (unless they're intending to just do all the puzzles!).
If we scored this test normally, then wouldn't the rankings be almost exactly the same order anyway? e.g. we're all penalized a similar percentage of our total score in the end, except the fastest solvers who get an increased lead now.

Now that the contest is almost over, I can explain what was intended using some numbers.
I've always believed and encouraged that LMI contests should run longer than the time top solvers take to solve all puzzles. This make sure that top solvers solve all puzzles and other get more time solve puzzles.

In this test, I was thinking at least 2-3 players can solve 24 puzzles in 90 minutes, and may be few more players in 120 minutes, and some more players should solve 22 or 23 puzzles in 120 minutes. If I'm running a test 33% longer than what a top solver can finish in, we need to give enough time bonus for top solvers. But I decided to not give any time bonus, instead reduce the point value of puzzles.

Rohan, Palmer and Thomas were one of the first few guys to participate, and looking at their results, I thought the timing is correct.
But that was not to be, 90 minutes was ill-timed, and if the point-reduction-system was not successful, it is because of wrong chosen Test.
As few of you have noted, a FLIP or a Broken Pieces kind of test will show its true value.

Without summarily accepting or rejecting it, I think we can give it a try again when we can plan a proper Test.

Congratulations to Thomas, Ulrich and Hideaki for topping in Twist.
Thomas solved all 24 puzzles in an incredible 86 minutes. Ulrich is the other one to solve all 24.

Among Indian results, Rohan is in top 10. That is an incredible performance IMO. Hope to see him get better.

Thank you everyone for participating.

I'm not completely surprised that all the discussion is around the point structure :-)

rakesh_rai - 2011-04-10 2:17 PM

On the other hand, this system will further tend to increase the difference between top solvers and others. Top solvers will get (699 PLUS bonus) but others will be penalized and they may get about 70-90% of their score based on when and what they submitted. Compared to previous systems, there is no change in top solvers' score but others' scores is lesser. If this is what is desired, then, yes, this system indeed serves its purpose. But I am not sure that is what is desired.

I'm not exactly sure if that is true.

If I ran this test for 120 minutes flat, motris would have got 869. This thing is one could argue for symbolic time bonus of 1 point per minute saved, but I always felt time bonus should be appropriately computed. Otherwise, it simply undervalues the exceptional performances by top solvers.

If the test was for 90 minutes, motris would lose 15 points to be at 719, but others would lose all the points they got for last 30 minutes.

Ok, agreed that the table above can't be exact since players' strategy could be different if the test ran for 120 minutes flat or for 90 minutes.
But I feel it provides very approximate information.

I liked the bonus system - I especially appreciate the motivation - allowing the average competitors to have enough time to make a good attempt at more of the puzzles.

I think it worked nicely here. (and, it helped, that the puzzles were all excellent)

Thanks :)
Ronald

I would be interested in the approach for missing breakpoints (the bigger one) ... if someone can point a couple of starting steps, that'd be great.

Edited by rakesh_rai 2011-04-11 8:55 AM

rakesh_rai - 2011-04-11 8:55 AM

I would be interested in the approach for missing breakpoints (the bigger one) ... if someone can point a couple of starting steps, that'd be great.

You can identify two missing circles (one in Column 1 and one in Row 1) without drawing a single line.
Did you get there?

I am very poor at such puzzles....I could get one missing circle for column 1, hopefully its correct...for row 1, still not sure. Here's where I have got to, so far. (I don't want to look at the solution before solving it completely)

rakesh_rai - 2011-04-11 9:17 AM

I am very poor at such puzzles....I could get one missing circle for column 1, hopefully its correct...for row 1, still not sure. Here's where I have got to, so far. (I don't want to look at the solution before solving it completely)

Given that it was solved by only 6 players correctly, I don't think you need to feel that you are poor at it.
The thing with Missing Breakpoints is that it uses 2 properties of standard ESB puzzle heavily. If you don't use it, the puzzle will turn out to be a trial&error.

Property 1 - About Corners
In a valid ESB puzzle, exactly 2 (out of 4) corners will have circles. More ever, these 2 circles will be opposite to each other.
So, using this property, you immediately put a circle at R10C1.

Property 2 - About adjacent circles.
Check the image below. If there are 2 adjacent circles, 2 of the 4 combinations are ruled out.

From this property, we can deduce that in the border rows or columns, 2 circles can not be adjacent to each other.

Applying this property, you can put a circle at R1C6 without drawing any line.

Using these 2 circles, you can proceed for upto this point

Both of those properties are part of a more general topological one that I found indispensable in my own solve (which goofed the end with two breakpoints in one row). In this particular puzzle, the breakpoints are placed such that if a square has a breakpoint turn where the majority of the square is outside the loop (any square on the edge has this property), then the turn must go up-right or down-left. Similarly, if the majority of the square is inside the loop, then the breakpoint turn must go up-left or down-right. This applies in reverse to turns which have no breakpoint.

Finally about Twists :

The EverGreens series at LMI were very popular, and Rakesh/Rohan wondered if we should do an EG3 at LMI. I was independently working on Twist, and I thought it might be a good idea to have Twist instead of EG3.

I decided to stuck to EverGreens format i.e. lot of easy puzzles and some hard puzzles.

Applying the twists were not easy, because I wanted a simple rule change to each puzzle. So all kind of Hybrids were ruled out. I'm personally happy with the kind of puzzles I chose. Even if the rule change is minor, the solving approach changes drastically in some puzzles (e.g. LightUp, Hitori). While in some other puzzles, one just needs to solve like the standard puzzle with the additional rule in mind (e.g. Fence/Minesweeper). But some puzzles resulted in completely different puzzles (e.g. ESB/Sudoku - unfortunately those two types turned out to be hardest ones). The rule changes to Masyu and Arrows are something I was not comfortable with (especially Arrows because it became too error prone).

Despite the debatable points-reduction system, I hope that everyone found some puzzles enjoyable.

And finally, thanks to Branko once more for pretesting all puzzles. I used his timings as a guidance in determining the points, but the timing structure of 90+10+10+10 was set by me, which could have been improved.

Considering that lot of puzzles turned out to be very different from the standard types, we'll probably should have EG3 sometime soon :-)

Ken, I'm glad that things worked out fine at the end.
Posting the password on forum is definitely not advisable while the test in running. If someone wants to compete the test unofficially, they should request for password in email.

tamz29 - 2011-04-10 9:13 PM

Excellent puzzles. excellent presentation.
Once again I fell victim to the answer format - miscounted arrows, miscounted cells... not a good feeling.

About answer format - I was very much impressed by the answer format used in TVC. Most of the answer keys were driven by that (all loop puzzles, minesweeper)
In EG2, the answer keys I chose were really difficult, but I'm certain that the answer keys in Twist were relatively easier.

There seems to be lot of wrong answers in No 3 in Minesweeper (Top), but I feel they are because of wrong solves rather than bad answer key. Same about Fence.

The answer key for Arrows were probably more difficult, but I didn't know of a better answer key. I personally know 2 players got it wrong after solving the puzzle correctly.

The answer key for LightUp was little bad - because in the top puzzle it didn't require to solve the puzzle fully.

Deb, thank you very much for wonderful test! I had very enjoyable 2 hours in the weekend. And of course i like the point system, i think it is very useful. I tried to solve hard puzzles in begining, some of them was solved smoothly, some of them not solved, and they caused some trouble for me. During the test i forgot some rule additions of some puzzles like hitori, like minesweeper, and i spent more time for these puzzles, i was a little upset for this. Because i can get easily more than 400 points. But anyway i like your puzzle style, contest format, nice instruction booklet, very useful points system. So thank you very much, and in my language "Tesekkur ederim" :)

Best,

Serkan

Deb, let me add my thanks for an excellent competition. Personally, I don't particularly care about the point system, but this one seemed more fun than most. For the 99% of people who are not going to finish in 90 minutes, it gave us something to think about. Thanks for the tip about the adjacent circles in Breakpoints, although knowing that meant the puzzle took me 2 minutes max, rather than the 30 minutes that I wasted not solving it in the competition :)

Thanks again.

Steve, I figured that your strategy of "solving all easy puzzles first before cracking the difficult ones" is best. I didn't follow everyone's progress so others might have followed similar strategy.
Congratulations on topping the UK chart this time.

The Missing Breakpoint properties mentioned above are really interesting. As a self-taught puzzler I tend to just hit everything with a hammer and hope it works. Is there somewhere online that people discuss these puzzle-solving theories?

kiwijam - 2011-04-12 3:38 PM

The Missing Breakpoint properties mentioned above are really interesting. As a self-taught puzzler I tend to just hit everything with a hammer and hope it works. Is there somewhere online that people discuss these puzzle-solving theories?

We try to do that for some puzzles in every test. But we don't do it consistently enough.
It is always interesting to discuss how the author expected players to solve a puzzle vs how players solved it.

Twist LightUps were not difficult by any standard (although they were not solved by many)

I had solving methods documented for them, so thought of sharing

Thanks Deb for this excellent test.

My original strategy was to try to solve all the easy puzzles and then some hard ones if possible, but I changed my mind because some puzzle types were so attractive that I really wanted to try both puzzles. Finally I solved puzzles only according to my likes, but still hoping to get at least the equivalent amount of points of all the easy puzzles ; and I did so despite some silly mistakes. So, good operation.
The puzzles themselves (the ones I solved) were very nice, and several were better than that. As expected, rectangles were fun to solve, as were masyu (especially the little one). Fences were pretty easy but, again, fun. Just forgot to send the answer for biggest one... Both hitori were excellent. I solved the second one after the test and it was really great (and a bit strange) to have so much pleasure on hitori.
I couldn't solve the biggest "breakpoints" but the smallest was nice too, etc.

All in all, an affordable test but with some tough puzzles for strongest solvers... Many beautiful grids... Nice job, really.

Ours brun - 2011-04-14 5:46 PM

Both hitori were excellent. I solved the second one after the test and it was really great (and a bit strange) to have so much pleasure on hitori.

I think this is exactly what Deb intended :-)