Blue and green rockers, yellow conrod and the base create a parallelogram.
The two rockers are connected to the base by universal joints of 2 degrees of freedom.
The yellow conrod is connected to the green rocker by a revolute joint and to the blue rocker by a spherical joint.
The mechanism has two degrees of freedom (by computer testing) so two actuators are needed for controling two pink frames.
Longitudinal axis direction of the yellow conrod is kept unchanged during motion. However its upper surface is not kept always horizontal.
The yellow conrod with two revolute joints has been tested but no success.