We made a 3-foot tall Eiffel Tower model. How do you say DIWire in French?!?
To make a 3D four-sided truss, you'll need to bend four similar 2D trusses.
Spot-weld or solder your lengths and bent portions together. We used 90-degree magnets to make sure our angles were clean.
There are all sorts of trusses. Here are just a few 2D and 3D examples.
A quick in-house strength test: Our truss holds stuff much better than wood does.