As we all know it is extremely tricky when it comes to making triangles out of technic pieces. There are several different ways to do it, but i just discovered a new way that i have not seen before over on brickshelf.com.
This comes from Sariel, who has created several creative projects. From what you can see in the picture it is very sturdy looking, and could be adapted for many different uses. The direct link can be found Here.
He has several other creations that are worth checking out aswell.
