Calibron Twelve Block Puzzle (Calibron 12)

myminifactory

The Calibron Twelve Block Puzzle appears to be a straightforward bin-packing challenge attributed to Theodore Edison in 1933 and initially marketed by his company, Calibron. The objective is simply to arrange all the pieces so that they form a rectangle (hint: create a 56x56 unit square). However, this puzzle's difficulty level is rated 5/5. Several variations of this puzzle have been created; in fact, one can be found on Thingiverse as I write this - but don't look at it because it reveals the solution. My Calibron 12 was designed from scratch to take full advantage of what 3D printers can accomplish. The raised dimensions on each "block" are accurately represented in units of 2mm (with allowance for printing tolerance), so the puzzle fits inside a 3D-printed box that is less than 3"x2"x1" - but the pieces are large enough to handle comfortably. This design was created from scratch using OpenSCAD. However, the part dimensions are widely available. My primary reference for the dimensions was actually this code which claims to solve the puzzle. No, I'm not going to show you the solution... I haven't solved the puzzle myself (yet). This is also why I didn't pack the pieces optimally on the printer bed -- don't want any spoilers now, do we?