Modular Structural Support Joint

While building larger structures with struts and joints like these:
http://www.thingiverse.com/thing:9359

I find that I need some more tesselation of the structure.

This set of things forms a simple joint which allows you to easily form more triangles within the boundaries of your structures. Of course you can do a whole lot more than just form more triangles, but that was the initial intent.

These things derive from a couple of things:
http://www.thingiverse.com/thing:8130
http://www.thingiverse.com/thing:8129

If you're doing a permanent structure, you could still use thing 8129, and stick a 1/8" pin into the hole.

There are a couple of key design aspects to these things.
1) They are symmetrically paired, which means you can place two next to each other (the 'half' form) and they will allow their struts to be at the same level. In fact, the interlocking nature of the pieces ensures that once you have two collars on the rod, they will not slip easily. That allevia