Trip-let blocks (like in GEB)
by zec, published
The attached OpenSCAD script allows you to create trip-let blocks: shapes whose projections along the x-, y-, and z-axes can be completely different. Probably the most famous trip-lets appear on the cover of Douglas Hofstadter's book GÃ¶del, Escher, Bach: An Eternal Golden Braid.
Instructions on how to customize the trip-let produced can be found in the comments of trip-let.scad. The script is very basic. Most notably, it does not detect whether the created trip-let actually has the desired projections or even whether the block is in one piece. You will probably have to experiment with various rotation settings before you find a workable trip-let.
A couple of example trip-lets from the script (including an approximation of one from the cover of GEB) have been attached in STL format. You'll need to scale and translate the model appropriately before printing.