This is a recreation of a really great model I found years ago, and have since lost unfortunately. This new version is pretty close to the original, and is fully parametric too if you want to customize it to your needs (use the .f3d file). I spent a lot of time scouring my hdd for the original and looking through my histories on Thingiverse and Printables but I just cannot locate the original, so to whomever first put this shape together I apologize I can't give you proper credit here!