Another modern invention we owe to a happy accident in Post-it Notes,those small pieces of notepaper that can be stuck again. In 1970, Spencer Silver was working in a research laboratory, trying to create a strong adhesive. He created a new adhesive that stuck to objects,but it could also easily be lifted off them. Because the adhesive was so weak, Silver considered it a failure. He shouldn't have. a few years later, a co-worker of Silver's was singing in choir. He used scraps of paper to keep his place in the song book, but the scraps kept falling out.