Parametric Printed SilkScreen w/ optional frame and squeegee

Converted the business card into a silkscreen stencil with optional frame and squeegee of the exact size. Also added optional text with, or in place of, image.

Many thanks to Anoved for pointing out how to get write.scad to work in the customizer. For some reason I can't respond to his comment, but the help is much appreciated and text now works online. For offline use, you need Write.scad and Letters.dxf from HarlanDMii

I've tested it now, but the size of text was really too small to pri