Hi I spotted on an MCAT book I am studying off of that the shading of the lobes(from a figure of p and sp3 orbitals) in an orbital represents the direction of spin for the electron and that in order for the electron density to overlap, the electrons must have the same spin. Firstly, I thought the shading represents the phase of the orbital, as in +/-. Is spin another way of saying phase? If this is indeed the case, this seems to conflict with the fact that electrons in one orbital must have opposing spins. Just a little curious, because this one portion of the book completely threw me off.