In 1968 a scientist at 3M named Spencer Silver decided to work on improving one of the most successful of that company’s products, adhesive tape. What was needed was a better glue that held more firmly, but still allowed the tape to be removed. By 1970, he had instead developed something very different, but of no use to adhesive tape. What Silver had managed to produce was a glue that was easy to remove but had only weak sticking power. Interesting, but seemingly a failure if there were no commercial uses for it. Four years passed, and then a colleague of the scientist commented that he was frustrated that the small sheets of paper he used to mark that day’s songs in his hymnal would fall out. The friend didn’t want to use tape because he was worried about harming the book’s pages. Finally there was a use for the weak glue that had been a mistaken result four years earlier. By 1980, the Post-it note was found in offices all over the world.