by Simon Greenwold. Vary the specular reflection component of a material with the horizontal position of the mouse. 

def setup():
    size(640, 360, P3D)
    noStroke()
    colorMode(RGB, 1)
    fill(0.4)


def draw():
    background(0)
    translate(width / 2, height / 2)
    # Set the specular color of lights that follow
    lightSpecular(1, 1, 1)
    directionalLight(0.8, 0.8, 0.8, 0, 0, -1)
    s = mouseX / float(width)
    specular(s, s, s)
    sphere(120)