Number of teeth of the fixed internal gear Z1 = 40
Number of teeth of two planetary gears (red and pink) Z2 = 38
Module m = 2 mm
The violet shaft has two 2 mm eccentric portions at 180o. The pink and red gears are on the portions.
Transmission ratio i = - Z2 / (Z1 - Z2) = -19
Rotation of the pink and red gears is transmitted to the blue shaft by four pins.