Brighten up your window with a gothic design from http://www.craftsmanspace.com/free-patterns/gothic-tracery-window-pattern.html.

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

For a single extruder combine parts 1 & 2 together and they still will make a delightful piece.

The print ready .x3g file:
0.1mm layer height
100% fill
2 shells
Left and Right extruders 210?
Took ~ 3hours