In high school I was briefly fascinated by a triangular "jump all but one" game, commonly found at Cracker Barrel restaurants. The basic premise is that any peg can "jump" over an adjacent peg to occupy the empty hole next to the jumped peg. The jumped peg is then removed. The goal is to continue jumping pegs until there is only one left.
The instructions on the face of the Cracker Barrel version of this game say, "LEAVE ONLY ONE -- YOU'RE A GENIUS". Wanting to claim the right to call myself a genius, unlike ordinary kids, who might just play the game a few times, I sat down on my Turbo-XT and started writing BASIC code. The algorithm I came up with ran a bit slow, so I directed output to my printer and let it run over night. In the morning the program was still chugging along. I advanced the paper feed on the dot-matrix lineprinter -- the kind that used continuous feed paper with perforated edges and holes on each side. Into view came 3 solutions represented by a string of numbers. A quick check verified that I was now a genius.
