Uses the default lights to show a simple box. The lights() function is used to turn on the default lighting. Click the mouse to turn the lights off. 

spin = 0.0


def setup():
    size(640, 360, P3D)
    noStroke()


def draw():
    global spin
    background(51)

    if not mousePressed:
        lights()

    spin += 0.01

    pushMatrix()
    translate(width / 2, height / 2, 0)
    rotateX(PI / 9)
    rotateY(PI / 5 + spin)
    box(150)
    popMatrix()