Bitbeam

Bitbeam Cube

Ingredients: 

12 1x27 beams

24 #3 and #4 Lego Technic axles

48 Lego Technic bushings or half-bushings

There were no nuts or bolts involved, and it assembles in a few minutes! It could use a couple of cross braces for stability, and I could upgrade it with 10-32 threaded nuts and bolts, but it's fine for now just sitting there looking pretty on my desk.

Each joint is a staple of grid beam construction - the "tri-joint". As they say in How to Build with Grid Beam, "If a stick won't make tri-joints, it's not grid beam, no matter how many holes it has." Bitbeam's ability to make tri-joints without helper cross blocks is the fundamental technical difference between Bitbeam and Lego Technic.

For a different kind of Bitbeam rapid prototyping, you can play around with Mr. Doob's online voxel editor:

BitbeamCNC (first prototype)

Here's a prototype X-axis for a Bitbeam-based CNC machine. Okay, it's pretty far from being fully armed and operational, but I hope you can see where this is going.