Parametric Single Toothbrush Stand

This is sort of a remix of [this toothbrush holder](https://thangs.com/designer/crashspeeder/3d-model/Quip%20toothbrush%20stand-975243) which was designed specifically to hold a Quip electric toothbrush. While I liked the original model, there were two things I wasn't as fond of. First, the angle. I found myself wanting to pick up and put down the toothbrush perfectly straight. Second, I found the original useful for brushes other than the Quip, which required slightly different dimensions.

While I started over on the design, it is clearly an homage to the original design to which it owes its concept and proportions. It should be easily adjustable to fit nearly any brush -- just measure or estimate what diameter tube it would take to hold it. 16mm appears to be just about right for the original Quip.