A Post-it note is a small piece of paper with a re-adherable strip of glue on its back, made for temporarily attaching notes to documents and other surfaces. A low-tack pressure-sensitive adhesive allows the notes to be easily attached, removed and even re-posted elsewhere without leaving residue. The Post-it's signature adhesive was discovered accidentally by a scientist at 3M. Originally small yellow squares, Post-it notes and related products are available in various colors, shapes, sizes and adhesive strengths. As of 2024, there are at least 28 documented colors of Post-it notes. 3M's Post-it has won several awards for its design and innovation.