It is possible to decorate glass in many ways. Decoration done by glassblowers at the furnace, when the glass is still soft, is called 'hot workingΓÇÖ. This includes different reliefs, as well as decorating optically and with glass threads and trails. Optical decoration is seen against light as patterns inside the finished glass vessel. This decoration is created by first blowing glass into a mould with grooves or a check pattern, and then finishing the vessel by blowing it freely into its final shape.
