[The_Reader_David]

An awful lot of mathematicians, myself included, have had the experience of working very hard to find a proof, going to sleep still feeling clueless about the what the right approach is, and waking up knowing the solution.

[Jigajog]

I don’t know if I buy it. I’ll have to sleep on it and see what I think tomorrow. Funny how scientist are able to confirm common sense.

[meowmeow]

I keep a big book of Sudoku puzzles next to my bed. I've found that doing a couple puzzles before I go to sleep helps me relax because I have to concentrate enought that I stop thinking about all the other stuff of the day. My theory was that while I might lay there restlessly mulling over the house renovation, work stuff, family stuff, there's no way I can lay there and mull over a Sudoku puzzle.

However, I've also found that when I get totally stuck on a hard puzzle and just put the book down, turn off the light and go to sleep, that the next day if I pick up that same puzzle, I will suddenly just whip out all the answers. It's kind of weird - I always wonder, how could I not see that solution last night...