Hi! I'm Simone, I come from Italy and I'm a newbie..glad to meet you...and ehm...I have already a question! My question is related about the example of human pyramid. There are 5 people, one at top of the other..like: o1 o2 o3 o4 o5 o5 push o4 up...o4 push o3 up and so on.. the perceiped force on the shoulders of o5 is only o4's weight or the sum of o1,o2,o3,o4 ones? if it is the last response, so must be o5 the strongest one and can they sit without difference of force on o5? thanks!