Crank 1, rotat ing about fixed axis A, is connected by turning pair B to slider 3. Slider 3 moves along circular guiding slot a-a of radius CB and with its centre at point C. Circular slot a-a belongs to link 2 which is cross-shaped and has extensions b which slide in fixed circular guides c-c of radius DB and with their centre at point D. The mechanism is equivalent to four-bar linkage ABCD.
$956$LG,4L$