A student volunteer stands on a turntable and is handed a spinning bicycle tire. The arrangement constitutes a system which is free to rotate about its z-axis. When the student changes the angle that the axis of the wheel makes with the axis of the turntable's rotation, the component of angular momentum involved in the change will be acquired by the student. It's most effective to start with the axes aligned and to have the student first turn it slowly sideways and then keep turning it upside-down.