Teachers: This can be a great challenge or contest for students. Use it in your physics, science, engineering, or shop classes. Use this for your mentally gifted students, too! Have the students study a machine, and tell how they could re-convert it to another type of machinery, without too much cost. This stimulates the creativity of our science students, too. A small prize and certificate might be a good incentive toward excellence, as well. Have a great learning experience in your classroo