Scaffolding platforms that hang above some studio sets are called Green Beds and are also known as cat walks. They provide a safe platform for crew members to work above the film sets.
The green beds are suspended from studio beams above the film sets with chains and steel scaffolding frames. These frames have wooden hand rails and a foundation to support the platforms.
Green beds are painted green to camouflage when being stored on studio backlots. There name came from being green and resembling bed frames.