This is a satellite drive developed from mechanism shown in “Revolution counter 1”. Input is green crank (carrier of this satellite drive).
Yellow gear (tooth number Zy = 50) idly rotates on blue gear (tooth number Zb = 51). Both are in mesh with pink gear (tooth number Zp = 10). Pink gear is also in mesh with a fixed grey gear (tooth number Zg = 51). Because Zb = Zg, the direction of the blue gear and the hand fixed to it is kept unchanged during rotation.
Because Zy is not equal to Zb there is a relative rotation between the yellow and blue gears.
The video shows two rev. of the green crank.
The hand and the dial on yellow gear show revolutions of the green crank.
Backlash in mesh of yellow gear and pink pinion doesn’t much affect the counting result.
In the past a similar mechanism was called “Ferguson’s mechanical paradox” because of strange behaviour of the two satellite gears.