I love Buback's OpenX Carriage, but wanted to modify the arm on the back. Before making modifications I wanted to redo this piece in OpenSCAD. I believe this is the exact same dimensions as the original. Uses nophead's polyholes routine too. Edit: Added a v2 version that adds some overlaps on the difference regions so it renders ok when rendering with the F5 key. If you're only going to print this, you could use either this or the original version this is derived from. The purpose of this derivation is to have an OpenSCAD version so it can be easily altered for future derivations.