include markers using quantum nano dots configured to emit light at a specific wavelength i e color when illuminated by another light further costumes and garments made for actors provide additional spatial volume associated with an actor that other actors will naturally avoid during a performance for example actors will generally avoid stepping on the long train of a wedding dress trailing behind another actor in another example a prop can be a rope or similar object functioning essentially as a u201c fabric u201d having a single strand this can be used by an actor to simulate the edge of a fabric sheet for instance such as when the actor portrays throwing back a blanket and springing out of bed in another implementation the substantially transparent material includes a metal mesh in one example the metal mesh is made of a flexible metal which can be formed into a variety of shapes the metal mesh has properties similar to tulle discussed above but with additional resistance to tearing and other forces alternatively a less flexible metal mesh is used to construct relatively rigid theatrical props thus providing an actor with a physical object with which to interact during a performance theatrical props thus constructed will not block the view of the markers attached to the actor in another example an object formed of such a flexible metal mesh is a large cup the movements of.