Shown here is the process of “creasing”. Creasing is decorative line applied into the edge of a piece of leather using a tool called a “creaser”. The creaser is heated and worked along the edge of the leather as shown in the photo. Creasing is a very traditional decoration method used on saddlery, harness, historic military equipment, and even modern belts. The purpose of creasing is almost entirely decorative but it does help compress the edges of the leather for a more finished look.