An example with blendMode("lighten") and radialGradient() building on @justvanrossum example.
size(1000, 1000)
fill(0)
dia = 864
offset = 120
rect(0, 0, width(), height())
d = 1200
blendMode("lighten")
radialGradient((350-offset, 750+offset),
(350-offset, 750+offset), [(1,), (0,)],
startRadius=5, endRadius=0.7*dia)
oval(350-.5*d, 750-.5*d, d, d)
radialGradient((650-offset, 250+offset),
(650-offset, 250+offset), [(1,), (0,)],
startRadius=5, endRadius=0.35*dia)
oval(650-.5*d, 250-.5*d, d, d)
