Pyramids are rigid. They are very stable, but very rigid. It requires the low base, the submission of the masses to keep aloft the point.
An inverted pyramid is completely unstable; that is, the masses are the top of the power structure, but will tip from that precarious location at a tap.
A truncated inverted pyramid, based in triangle instead of a point, has the best of the two previous systems. It keeps the individual freedom that the inverted pyramid style began with, and some of the stability of the regular pyramid.
Communism: You can imagine a flat piece of cardboard supporting a REALLY tall bottle cap. The masses stay at the bottom, but the leaders are precarious.
Anyone got any more?