Puzzled over their diagrams @ fallbrook tech.

Thought it was a few Big Balls in there .. Have some of those hubs, in bikes in the shop.

I try to explain those referring to the circumnavigation closer to the Poles being a shorter distance than at the equator
so the distance shorter takes less time to go around
Relative input and output distances result in the ratio differences

having a town on a River with fishermen they understand navigation better than those inland where things look so Flat,