2013-12-26 Figure of the spherical harmonics basis (low band L=0,1,2) References "Spherical Harmonic Lighting: The Gritty Details". Robin Green. http://www.cs.columbia.edu/~cs4162/slides/spherical-harmonic-lighting.pdf "Stupid Spherical Harmonics (SH) Tricks". Peter-Pike Sloan. http://www.ppsloan.org/publications/StupidSH36.pdf