# set a gradient as the fill color
radialGradient(
    (300, 300),                         # startPoint
    (600, 600),                         # endPoint
    [(1, 0, 0), (0, 0, 1), (0, 1, 0)],  # colors
    [0, .2, 1],                         # locations
    0,                                  # startRadius
    500                                 # endRadius
    )
# draw a rectangle
rect(10, 10, 980, 980)