The strut width has been deliberatelty increased to show the geometry.
Tetragon strut [face] has been designed to facilate modular construction in wood, but without the trouble of cutting mitred ends. Note that the strut length is shorter than its associated quad-edge. Again, these struts are meant to be fixed on the interior face panel; however they may also be used with flange hubs of the kind shown below:
The strut profile is the same as for mitred struts. Should you desire bevelled struts, angle sigma provides the cutting angle. All strut faces are guaranteed coplanar.