Input: pink crank rotating regularly.
Yellow intermediate crank rotates irregularly.
Output: green crank rotating regularly.
The input and output shafts are coaxial and rotate in opposite directions at the same velocity.
All axes of the revolution joints are concurrent.In order to avoid collision of the violet conrod with the blue one, the violet conrod, yellow and green cranks have strange shapes.
It is a study to show that the mechanism has the same function of 3 bevel gear drive.