Abstract: The present invention is an improved method and apparatus for supplying electromagnetic energy to a body having at least one substantially planar surface comprises moving over the planar surface a self-propelled container housing a source of electromagnetic energy and having an open side which is substantially perforate to the electromagnetic energy thereby permitting transmission of the energy from the container to the body while all other surfaces of the container substantially block transmission therethrough. Concurrently with the movement of the container responding within the container to at least one selected parameter to control the movement of the container over the planar surface.