Tunable Tolerance Tetrahedron Twist Timewasting Toy

myminifactory

This customizable tolerance tetrahedron twist timewasting puzzle toy was inspired by http://www.thingiverse.com/thing:186372 . The issue with that thing was that it was just an STL file, lacking a means for adjusting the "fit" tolerance or scaling on its own. So, one of my lab students, Zachary Snyder, devoted valuable study time that should have been spent preparing for final exams to derive his own formula for it in OpenSCAD... and then I wasted too much time trying to print it with various parameters and tweaking the design. Oh yeah, it also takes a remarkably long time to solve the puzzle... especially astonishing given that it's just two pieces! The 20160630 version boasts a few minor but significant improvements. The original version employs a turn of 1.0, which causes the parts not to fit with those from the new design unless tenth_turns is set to 10 instead of its new default value of 12.