Why not take a piece of tracing paper and then transfer that to 4 sq. per inch graph paper. (Put it up to the window to transfer it.) Then you can break it down to a pattern, using 4 sq per 12" total block. Often you will find this to be quite easy. Just do one little square at a time and hopefully you will surprise youself with a pattern you find useable! THIS is how I often take something I like and go with the flow! I teach a class and they too find it interesting to do this type of 'copying'.
Good luck!