Coin Rig Test
A whimsical little rig I made
The normalized orientation vector of the control (tempered with an aim constraint to prevent rotation) drives the pivot position of a cylindrical transform.
The roll attribute runs an expression that drives the offset rotation required to correct for the mismatch in the coin's circumference vs the adjusted circumference of the coin's path, based on the previous calculation; that way, the coin's offset rotation will be preserved when the path radius value changes.