A strange little side quest
Zoom out from Christmas Chain for a moment and the timeline gets surprisingly deep. Alexey Pajitnov created Tetris in 1984 after drawing inspiration from pentomino puzzles, then simplified the idea around shapes made from four squares. The timeline takes another interesting turn: Spacewar! appeared on MIT's PDP-1 in 1962 and became one of the earliest influential computer games shared among programmers. So a round of Christmas Chain is not just a quick distraction; it is a tiny stop on a much longer puzzles timeline.
