I bet the mandolin(?) players weren't exactly comfy though - "BIG smiles, dears!"
The magnets on those gongs/bells would be really handy for picking up swarf in the workshop. Or finding my keys anywhere in the house They must be individually-tweaked electromagnets - permanent ones would be too dangerous and too hard to set up.
You have to admire the thing, but I wouldn't have wanted to be on one of those wires during rehearsals!
E.
PS: Seriously, it's an impressive piece of stagecraft.