I designed this to use dual extrusion but parts 1&2 can be printed together for a nice single extrusion/color piece too.

Make it into a "stained glass" piece by sandwiching a piece of coloured celophane between two of these.

The base design is from http://www.craftsmanspace.com/free-patterns/gothic-tracery-window-pattern.html.

Successfully printed in PLA on a Flashforge Creator.

The original Solidworks models are also available for download.