Platonic: core math concepts

[awr1]

FWIW I've been using static ranged dimensions for a while in my own (short, 2-4 
dimensions) vectors + matrixes plus distinct types for unit vectors, colors, 
etc. and I really find it quite easy to deal with. (Though my context is 
graphics/game engineering, not ML/numeric processing, so my comments are not 
going to be very helpful here)