Lately I’ve been working the core engine math library, and as a result had to delve into the wonderful world of “handedness”. This part of implementing a cohesive math library has always been a stumbling block for me in the past, so this time around things are much clearer. Here are some of my notes.
LeftHanded Coordinate System  RightHanded Coordinate System 

Matrix Layout: Row Vectors  Matrix Layout: Column Vectors 
Matrix Multiplication:
[pmath size=15]M = M_1M_2{cdots}M_n[/pmath]

Matrix Multiplication:
[pmath size=15]M = M_n{cdots}M_2M_1[/pmath]

Polygon Winding: Clockwise  Polygon Winding: CounterClockwise 