Three weekends ago, that would be March 30 – April 1, I guess, we did an old jigsaw puzzle of computer languages, probably computer languages as of the mid-70s. It included punched cards, punched paper tape, and Fortran on coding forms. Like this —
It turned out to be pretty easy because it was easy to figure out which concentric circle held any given piece. The best thing about it, besided it being an fun level of difficulty, was that it was one of the era of Springbok puzzles printed on really thick, solid cardboard with pieces that fit so well that you can hold the finished puzzle up, like this:
No glue, nothing behind it, just the puzzle.