It was really interesting to work on this drawing, it was at the same time a kind of technical challenge, and also a real pleasure to do it :)
I first made a sketch with different symmetries (circular around the eye and axial to the diagonal), with main lines, circles, parts etc... just to locate elements
After that I recorded the bottom right part, and then I wrote a script (in c++ and OpenCV) to crop, flip, and assemble it.
I'm glad you like it!
I think I will soon do another "4 hands" drawing ;)