Here I've shown some of the concept sketches for elements in the frame, the full drawings I don't have access to right now, but the false perspective was built in to the set by drawing the cages in diminishing heights and angles to the back of the frame.
Due to the depth of the set, spread of action across the frame and overlapping of cages, there were complicated breaks in the set to shoot in passes that relied on a fixed camera position and selection of lens as they used the perspective lines to build in break lines that would work. The finished set would only work keeping those lens and camera position decisions locked in.
