MikeC

Hi Francois,  I wish it was my idea but unfortunately I'm not creative enough to invent that.  I can't remember the person's name.  He posted on MN a long time ago a link to the instructions.  I printed the instructions and followed them to make the drawing.  He has a website where he sells the instructions.   I'll try to find it for you.   To be honest I think your drawing method is simpler and therefore probably more likely to be historically correct.   There is also another drawing method other than this one that uses a three bar linkage that is really interesting also. It exactly makes the C bout curves with one smooth drawing line which is really interesting when you see it for the first time.   I'll try to find a link to that one also but it's difficult to understand the instruction on that one.  

Oh sorry,  I thought it was you that posted it.  It was DoorMouse,  my mistake.     Nice photos on pinterest thanks!