2d doughnut

Blue donut :-)

cairo.Arc(320, 240, 30, 0, 360)
cairo.Arc(320, 240, 70, 0, 360)

cairo.SetFillRule(CAIRO_FILL_RULE_EVEN_ODD)

cairo.SetSourceRGB(0, 0, 1)
cairo.FillPreserve()

cairo.SetSourceRGB(0, 0, 0)
cairo.Stroke()

Inner radius 30, outer radius 70 pixels.