This isn't something I read in a book or anything, it's more of a puzzle I thought up for myself.
However, I am unable to find a solution.
Here's my problem:
If I create a 9x9 checkerboard, and want to walk a path across it, where each block is walked upon only once, and there are only 90° turns, it's easy enough to create any path. (See first image example:)
However, if I want to create an entrance and exit point NEXT TO EACH OTHER, I am stumped. I can't do it:
Can someone help me think of a path ac cross a 9x9 area, where the entrance and exit points are directly next to each other, and yet each block is used only once and only 90° turns are used?