In the past few years, we have seen plenty of cool transformable robots here. The OmniWheg is also worth a look. It is a clever robot with separable omni-wheel and 4-bar linkages that can transform from wheeled to legged mode. This way the robot can move in all directions and change shape to overcome stairs.
As you can see in the video, the OmniWheg changes the shape of its wheels to climb stairs. Pretty neat, don’t you think?