A silly diffuse shading model

Neat way to introduce Hermite Interpolation from a practical approach!

And not even that silly! These not-so-physically-based approaches don't get as much love as they should in the current graphics literature IMO. More of these would be sweet!

Nice. I've been using the remap + squaring trick for a while, but it never occurred to me that the differential of the function was identical at the limits, that's great! As alluded to in the article, it's also a reasonably convincing yet stupidly cheap approximation of sub-surface scattering for various materials and works great for things like leaves and other very thin surfaces.