In 1968, a 3M chemist discovered a glue that was strong enough to bind to a surface, but weak enough to be removed and reused many times. It was, essentially, faulty glue. Flash forward six years to a church in Minnesota, where a 3M engineer was singing in the choir, frustrated that the bookmarks in his hymnal keep falling out. Suddenly, a light bulb goes off: What if he applied the "faulty glue"? They would stick easily, but not permanently. An idea was born: He began handing out his sticky-but-not-too-sticky bookmarks to employees at 3M. They were a complete success.