Parameterized drain screen

After losing a toothpaste cap down the sink, I decided to create a screen to catch objects, but still allow water drainage. The design is parameterized so you can use OpenSCAD to generate a drain screen personalized to your sink configuration. It consists of a top plate with square holes in it, and a short sleeve that fits inside the inner diameter of the drain pipe and centers the screen.

Note that on my poorly tuned MakerBot, producing a fine rectangular grid is very tough, so the default