Post-it Notes
In 1968, Spencer Silver, a chemist working for 3M, stumbled across a “low-tack” adhesive that he found was just strong enough to hold paper to a surface but weak enough that it wouldn’t tear upon removal. After many failed attempts at finding a marketable application, one of Silver’s colleagues, Art Fry, realized that it would be perfect as a no-slip bookmark, and the Post-it Note was born.