It is proven that the paper clip was well known by 1899. A patent was given that year for a "machine to make wire paper clips" to William Middlebrook on April 27. The drawing in the patent shows a Gem paper clip. There are many different kinds of paper clips. Some have ends instead of round ones. Some have a bent end. This was done so that it is easier to put paper in. Some of them have wires with bumps that allow them to hold the paper better. Some paper clips are made to look good. They are sometimes in a triangle or a circle.