In this video, we build many different versions of Ed's PMH, to learn how that device may have been able to lift very-heavy rocks at Coral Castle? It seems to be based on "circular magnetism", which can exert a strong pulling-force on a nearby iron bar. Essentially the opposite physics are used in "electric railguns", which repel iron bars! Ed's inventions have not yet been appreciated by modern academic physicists. The PMH could be used industrially as a special kind of lift magnet.