Meet the Oncilla Robot: a 5.1kg open source quadruped research robot with pantograph legs that can exhibit agile locomotion. As the researchers explain:
its spring-loaded pantographic leg design compensates for overdetermined body and leg postures, i.e., during turning maneuvers, locomotion outdoors, or while going up and down slopes. The robot’s active degree of freedom allow tight and swift direction changes, and turns on the spot.
The above video from Dynamic Locomotion Group shows this robot in action.