An exploration of what a crossword puzzle on a Möbius strip would look like, prompted by historical research into Robert Guilbert's 1986 puzzle game 'Pago Pago.' The post traces how a speculative claim about Guilbert's Möbius-strip crossword became repeated as fact across academic and popular sources. It then dives into the mathematical constraints of designing such a puzzle: because a Möbius strip is nonorientable, letter-forms flip parity when traversing the loop, limiting usable letters to those with the right axis of symmetry. The author constructs a diagonal 'ladder' crossword using letters like O, X, L, W, H, C, and D that survive the half-twist transformation, and shares a printable strip where solving the first five clues lets you read the remaining five by flipping the paper over.
