Post Cup Holder

We have some nice furniture made from wood posts, and I love to sit down with a good read and a cold drink. One day it occurred to me that I could make a cup holder that would sit on top of the wood post so I wouldn't need a table next to the couch. Hence was born this thing.

As a side note, this is the first thing I've created using OpenSCAD, and my first use of customizer. In this case using customize makes a lot of sense because each post on this couch is a different diameter.