Looking at a deck of cards got me thinking about the design of playing cards and how it evolved. That led me to some excellent pages on the English Playing Card Society Web site, specifically the history and design pages. Evidently, cards used to be square-cornered, had plain backs, didn’t have numbers in the corners, and were “single-ended” (meaning that there was a right side up to each card). Over time, the design of playing cards was tweaked to give the cards round corners (it happened anyway), patterned backs (to prevent card sharks from easily marking cards), numbers in the corners (to more easily and quickly identify and sort the cards in your hand), and two ends (better than the less convenient “right side up” cards). A good study in functional design.