This is not a pattern but a picture on Pinterest. Maybe you could use it and come up with your own pattern?
https://www.pinterest.com/pin/203717583116777116/
This is a mouse pin cushion pattern that could easily be changed to a pot holder.
http://www.connectingthreads.com/Pat...__D10382D.HTML
And, if you are wondering how to layer the hot pad.
http://www.instructables.com/id/How-...r-Mothers-Day/
And another pinterest image that shows the basics of a mouse hot pad.
https://www.pinterest.com/pin/137570963588561801/