Planetary mechanism with face gear.
The green gear (Z1 = 40 teeth) is fixed.
The yellow gear has 30 teeth (Z2).
n2/nc = (Z1+Z2)/Z2 = 7/3
nc: velocity of the blue crank
n2: velocity of the yellow gear
Unlike ordinary spur planetary mechanism there is no constraint between Z1, Z2 and tooth number of the pink gears.