Note the spin of the ball and that it exits without spin in the direction that it entered. Isn't it extraordinary that the ball returns almost exactly along its entry path? A light beam certainly wouldn't do this, so strengthening the case for exercising caution when referring to the "particle theory of light". The particle theory of light assumes that the particle has mass but no moment of inertia and that it has no physical size. I've never seen a ball in the playground that fits this description!