Tank3d Bottom triple corner L+R 20x20 aluminum extrusion

Self align and self square triple corner for 20x20 aluminum profile. Part of [Tank3d Printer](http://www.thingiverse.com/thing:2040664) , many more things there, take a look.

Similar to [Tank3D Triple corner 20x20 aluminum extrusion](http://www.thingiverse.com/thing:2058034) but with the difference that there are L and R version and one of the bars is not on same level

Very strong, at the same time almost invisible as it is designed to have same thickness as neighbor aluminum profile.

U