Gothic Tracery
Cathedral windows drawn with compass and straightedge: pointed lights under foiled circles, rose windows and intersecting tracery, glazed in color.
Pens
Black stone, blue lights, red foils and gold spandrels. More pens split out every other light, the smaller foils, the moulding lines and the frame. Starts with 4 pens and works with anywhere from 1 to 8.
Settings
Style, Lights, Arch sharpness, Height, Petals, Rings of petals, Mullion width (mm), Taper, Large circles, Foils, Cusped heads, Moulding lines, Glazing, Spacing (mm), Border (mm).
The preview uses the default settings on A4. Press R in the app for random variations. The SVG export is in millimeters with one Inkscape layer per pen, so it works with the AxiDraw extension, vpype and saxi.