> Quibbling: Stackability and therefore wall thickness are relatively > new. Remember, old skizool icehouse pieces were solid. > So you might have the what, but probably not the why. Good point... So how was the original, solid medium's size determined? As the median between the small and large base? Seems so: (1 + 9/16) / 2 = 0.78125 = 25/32 And, thus, wall thickness became "forced" to be--at most--0.21875? Which, divided by two, give you the wall thickness (actually, it gives you the length of the wall thickness along the horizontal; the actual wall thickness must be derived using half the angle of the peak and some trig). So, yeah, I'm off on the history, but I still think the method is dead-on. What would that be, as a formula? For any give pip value X: Base = (Base of X-1) + 0.21875 Height = ??? (I can't find out how to derive the angle from Height and Base, and so I can not find how to use some trig function of that angle with only the Base, to determine the Height after the above simple addition. Anyone here know all that stuff?) David