The performer walks staying close to the wall. The oversized head is lightly pushed against the wall at all times to create enough traction for the sphere to rotate around its axis. As the performer walks – the head spins.
The spherical head is made out of a sturdy, light material, and a simple circular apparatus (involving tiny wheels) is attached to the head of the performer. This allows for a seamless rotation of the sphere (when in moving contact with the wall)
Brief video demonstration is at: https://www.youtube.com/watch?v=7n6fqj8pc6M