rack hangers

These parts are for hanging things in 19" computer racks (and other places).
The rack hanger was specifically designed to fit in 3/8" square holes in various places on the rack. These can be printed in either a hard plastic like PLA or TPU.

These parts are meant to be used with a loop of string in a [cow hitch knot](https://en.wikipedia.org/wiki/Cow_hitch).

The string hookend is designed to have a loop of string hitched over it, and then wrap the loop around a bundle of wire, and pass the hook end between the pair of strings that make the loop. For this to work, there must be enough tension on the string to keep it in the hook.

If the rack has two holes next to each other or a hole near an edge, the string loop can be hitched over the edge. If only a single square hole is near by, the rack hanger can be used. If the rack has a large slot connected to a square hole, the hanger with string attached can be passed through and then slid into the square hole and pulled throug