Cool! A very nice read.. thanks for sharing. I actually looked at that puzzle but decided strawberry fields was more interesting. My solution comes up with reasonably efficient answers within a minute or so, even on a 1000h eeepc :) I don't have a nice writeup like you but the README contains a brief explanation (in concordance with the rules for the puzzle): https://github.com/BruceJillis/Strawberry-Fields I decided to post this because you mention constraints and my solution is written up in a constraint logic programming language (eclipse), it might be interesting to translate your solution and compare.