Today I learned that on a chessboard, a knight can visit each square exactly once. Here's how: The animation is actually one way of solving the Knight's Tour, which is a mathematical problem that is commonly given in computer science courses. (However, I don't recall ever giving this problem in my Intro to Java class.) At first glance, viewers may object that the animation is not valid considering that the knight's square of origin is incorrect. However, according to Wikipedia, there are 26,534,728,821,064 different ways (including reversals, reflections and rotations) to do this so that the knight travels in a loop (ie, starting where it began), in which case you could start from any square and then just continue the loop from there. Via Reddit....