A photon has a spin of 1, while an electron is 1/2. I've heard it said that the electron needs to spin 720 degrees to complete a full cycle. Is there any proof that the electron is spinning 720 degrees and not just spinning 360 degrees, but at a lower harmonic of the photon-- 1/2 the photon's spin frequency? As an analogy, 2 pendulums of proportionately different mass, suspended on the same string will "feed" off each-other. If you start the lighter pendulum swinging, the heavier one will start swinging too, but at a lower frequency (and vice versa). Depending on the mass proportions, you can get the heavier one at frequency 1/2, 1/3, 1/4 or whatever you like along that line. Let's say you have it at 1/2... if you measure a whole cycle in the lighter pendulum, you'll only measure 1/2 cycle in the heavier one, but both of them are still covering the same amount of degrees.