If Google Image search is your sole barometer, “design thinking uses just one tool: 3M Post-Its,” says Pentagram partner Natasha Jen. “Why did we end up with a single medium? Charles and Ray Eames worked in a complete lack of Post-It stickies. They learned by doing.” In her provocative 99U talk, Jen lobbies for the “Crit” over the “Post-It” when it comes to moving design forward.