customizable coaster with holder

What is better than a cold beer ?

A cold beer with a coster below is better than having wet circles on the
table - at least my wife says so, dunno where she get this ;-)

So here is a customizable coaster generator with optional text on it,
or a simple circle design and a customizable coaster holder for them to stack.

The uploaded files are generated with a thickness of 3mm and a diameter of 100mm.

But feel free to generate what ever you like.

[ 04'2025: added a bn-coaster_2lines.scad version - just fiddle with the
offset and stretch for better placement ]