Block and Tackle

I needed a block and tackle to lift hay bales in my shed. I found this one here by Mysabre73:
http://www.thingiverse.com/thing:963214
but it was too big for my 150x150 Printrbot Simple. I got it printed at 90% but figured I'd rather have 608 bearings on the pulleys so it ran a little more freely and lasted longer.

So I whipped up some OpenSCAD files and got it done.

Update 1: I found out how to join circles by tangents rather than direct to a perpendicular radius. Version 2 of the *.scad and *.stl files use the 'hull' function. I haven't printed this version yet, but it should be neater.