Input: green pulley.
Output: pink crank interruptedly rotating 90 deg.
Input and output are coaxial.
Blue slider moves in runway of the pink crank. Its blue pin moves along inner profile of the stationary guide (in glass).
Yellow T-shaped part is pivoted on the blue slider pin.
A surface of the yellow part always contacts with the guide outer profile. The yellow part has a pin that moves in slot of the green input pulley.
The yellow part has complicated motion: successive translation and rotation.
In this video the ratio of motion and dwell periods i = 1. It depends on the distance between inner and outer profiles of the guide.
The side number (n) of the guide deteminds output rotary angle A.
A = 360/n deg.