Yin-yang
// Under a shell type: box -l g yin-yang.box
// ---
// Here we show how Poly can be used to trace curves
include "g"
w = Window[][
b = 0.4 // border
r = 10.0 // radius
rr = 2*r, rs = 0.25*r
BBox[bb = rr + 1, (-bb, -bb), (bb, bb)]
Circle[Style[Border[color.black, b]], color.white, (0, 0), rr]
Poly[color.black, 1, (0, rr), (r, rr), (r, r), (r, 0), (0, 0), (-r, 0),
(-r, -r), (-r, -rr), (0, -rr), (rr, -rr), (rr, 0), (rr, rr)]
Circle[color.black, rs, (0, r)]
Circle[color.white, rs, (0, -r)]
]
w.Save["yin-yang.png", Window["rgb24", .Res[Dpi[100]]]]