Input: pink disk of two slots and two violet pins. It rotates continuously.
Output: blue cross of four cyan pins.
Yellow cross is mounted idly on the blue cross.
Red spiral spring tends to turn the yellow cross clockwise. Small blue pin acts as a stopper for the yellow cross. The spring forces the cyan pins to enter the disk slots.
In one revolution of the input, the output turns 90 deg. and pauses two times.has the same feature but its output acceleration is larger.