It was not until 10 years later than Arthur Fry, another research worker in the 3M group, found a use for what was to become the Post-it, again purely by chance. He was a member of a choir and was trying to find a way of marking the pages of his music book without damaging the paper. And this was why, in 1980, he put a thin layer of this famous "unknown" adhesive onto the page markers of his score . . . and it worked! The little pastel-colored pieces of paper that stick, unstick and can be re-stuck at will came into being. The name Post-it was invented in 1981. (Inventions and Discoveries)
A microscopic photograph of a Post-it note. Spheres of resin are sunk into the paper, and each time the paper is pressed, bubbles burst and glue is released.