For the first puzzle:



First the red. There is only one option for the obtuse vertex at the bottom. Also, the C has to connect down to the E, and you quickly run into problems if you try to connect it to B as well, so it has to connect to the acute vertex to the right.

Now the blue. There is only one way left to connect the H without cutting off the bottom right acute vertex, and the G then has to connect up to guarantee a single, non-crossing loop. The B then has only one option, then the D, then the A.

Finally the green connects up the last few vertices.


For the second puzzle, the right angle vertices are pretty constrained, so start with those. There is a clever trick you have to notice after this, but I thought it was very impressive so I don't want to spoil it in the forum (you can always check the solution pdf if you want to see it).

Edited by ghirsch 2016-02-05 11:17 AM

Sorry for the late comment, but thanks for all participations and lots of positive feedbacks. And congratulations to Robert Vollmert for his dominant victory! My only regret is that I was sleeping while he was playing.

As we stated in the password, we've started working for Vol.4. If any readers have some suggestions to our book, such as "more hard puzzles", "less T&E puzzles" or any particular genre you want to solve, please let us know.

Here are two related links:
1. EKBM has posted his thoughts about this test in his blog (http://ekbm.blogspot.jp/). Logical solving path of Graffiti Snake 2 is beautiful and worth reading.
2. German website croco-puzzle (http://www.croco-puzzle.com/) is holding a daily competition of Toketa Puzzles. First two puzzles are New Tren by Silke Berendes.

Thanks James and Hideaki. James, you were definitely on the list of solvers that I was scared off while reloading the score page all weekend + Monday. And Hideaki, looking at the croco series, good thing you were test-solving!