Animation with polygon points not working

[nilamo]

In your loop where you apply the sine, add a before/after print, like so:

    before = gPlane_p2_y
    for degree in range(361):
        y_value = math.sin(pi / 180 * degree)
        gPlane_p2_y += y_value
    print("{0} => {1}".format(before, gPlane_p2_y))

You'll quickly see that gPlane_p2_y (the only value you change) is pretty much always 360, which explains why you don't see any movement... because none of the numbers are changing.