There is a specific rhythm to starting a new jigsaw puzzle. You crack open the box, listen to the satisfying rustle of cardboard pieces hitting the table, and flip them over one by one. For the vast majority of puzzlers, the next step is non-negotiable: you sort out the edges.

You have likely spent a rainy Sunday afternoon hunched over a table, sorting through hundreds of cardboard pieces. There is a specific satisfaction in finding two shapes that lock together perfectly. But as you pieced together that landscape or famous painting, did you ever stop to ask: Why is it actually called a jigsaw puzzle?