Some stuff on gears

The math problem is a piece towards investigating gears, but also, in the other direction, towards the geometry and trigonometry behind the shapes and motions happening in the gears -- towards some grasp of calculus... did I lose you yet? I'm still figuring out how many pieces, and where from, I need to satisfy my curiosity.

Type of Gears <--some cool lego stuff here too
Epicyclic gear trains and the math calculations of
this page on timing gears from this online book Construction Mechanic Basic V.1

this is a cool site -- not quite what I am working on now, but soon... clockworks