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://w