Board Thread:General Discussion/@comment-25548156-20130814194325/@comment-25790839-20150113175231

MinecraftPercabeth wrote: HTFCuddles wrote: Well, the glasses on the Bill Cipher wheel were drawn, so they probably weren't comepletely accurate. Well, everything in Gravity Falls is drawn.

He is saying that this was drawn by the Author, who is a character in Gravity Falls.