They say the best ideas are the simple ones. A person can sketch something in just a few minutes to include a single, unifying message. So often throughout history, great ideas have come from simple moments.

We’ve all heard the Beatles’ classic Yesterday. According to the composer Paul McCartney, the song came into his head before even opening his eyes one morning. It was so complete that he had to research to make sure he hadn’t stolen the lyrics or melody without realizing it. From a waking moment, one of the most famous songs of the 20th century was born.

Designer Paula Scher said some of the best ideas can be sketched in the course of a meeting. Of course, that’s not always the case for everyone — Freddie Mercury spent years working on Bohemian Rhapsody. But it does seem that the best ideas are the simplest ones.

Inspiration can strike at any moment. When it does, people reach for whatever they can to make sure they remember it — tissue paper, books, envelopes, and napkins. And often, that’s what changes the world. Here are 65 ideas that got their start on a napkin.