Despite their success today, sticky notes were not always commonplace at offices and schools. [3M chemist Dr. Spencer] Silver was trying to make "bigger, stronger, tougher adhesives," something with a mighty hold. Instead of the powerful stick he hoped for, what he created was the opposite: "microspheres," tiny particles that stay sticky but are removed easily from surfaces. Although Silver missed his initial goal, he knew he designed something revolutionary. His persistence finally paid off in 1973, when his adhesive caught the attention of 3M employee Art Fry. The two worked hard to convince others of the adhesive's usefulness. It took them several more years to perfect the design, but finally, with the help of other scientists, they had it: a thin film of the special adhesive along just one side of a piece of paper. In 1980—12 years after Silver's fateful discovery—sticky notes were sold in stores and found instant success. Indeed, sticky notes may be the most valuable "mistake" in invention history!