Hey Dave! This was the best one yet, some more advanced questions here, and an excellent explanation overall. Two questions: 1) if we have the "no tread depth less than 6in", why do we also have the 12' / 10" rule? It seems to me, that if we have both, the bend angle of the stair, per step, has a minimum level. If we used that as the requirement, we could reduce to a single rule. 2) You did a good job explaining the problem of the square stair bend, but I need to see a good example of how a square turn stair is really done then if we have a requirement of 6in min tread depth AND the 12"/10" rule. It seems to me that there really is no square turn stair anymore, we will have a different configuration, but I am having trouble seeing how it looks.