Customizable Modular Snowman

Goals:
1) To derive all of the dimensions for any size snowman from a single parameter, the diameter of the bottom snowball.
2) To have the ability to print a snowman in one piece or multiple pieces.
3) To force all vertical dimensions to be an exact multiple of the chosen printer layer height and all horizontal dimensions to be an exact multiple of the chosen nozzle diameter.
4) Continue to develop my openSCAD programming skills.

There are two main parameters, the desired part name and t