DrawingBot in OpenSCAD

Background
Some time ago I decided to build a new project, and picked the *DrawingBot* by *MakerC* (https://www.thingiverse.com/thing:1517211). A bit of research also picked out the remixes by *avanhanegem* (https://www.thingiverse.com/thing:2058866) and *henryarnold* (https://www.thingiverse.com/thing:2349232) - their excellent ideas, designs and other contributions have all been considered in this re-design.

After looking at the original designs l decided that I wanted to make some changes - mostly to the idler pulleys and GT2 belt fixing, but also to tidy up a few loose ends that had irked me a little (e.g. limit switch fixing holes). Unfortunately I had no access to the original design files so had to make my own using OpenSCAD.
Design basics
My design is not as pretty as the originals, as I was too lazy to design the nice curves and neat linear bearing supports (mine are fixed with cable ties). The pieces are mostly straight-edged, albeit with nice curved corners.