Cartoon of spin-orbit coupling
Cartoon of spin-orbit coupling using a classical approach of representing the magnetic fields created by the orbiting electron (p-orbitals and higher l-values) and the intrinsic electron spin (which is where the classical analogy breaks down, as there is no counterpart to electron spin in classical physics) as bar magnets. The parallel configuration are energetically less favourable (i.e. higher) than the anti-parallel configuration.
Two versions are available: either with stationary arrows representing the B-field line directions, or one in which the arrows orbit around the “current” of the rotating electron. The latter looks nicer, but might cause some confusion or misconception of what magnetic-field lines do.