(Lengthy) Replace each of the cubes with a simple robot. Each robot will have movable joints at the shoulders, elbows, hips, and knees. Use the numeral keys to let the user pick the relevant joint. Let the shoulder and hip have full 3D rotational degrees of freedom. Let the elbow have just two rotational degrees of freedom, and the knee just one rotational degree of freedom. For joints with 1 or 2 degrees of freedom, you should store these as Euler angles corresponding to rotations about the appropriate (e.g., x or z) axes. The body parts should be drawn as non-uniformly scaled cubes or spheres.