In each individual or every system, there is always a limitation of its own. The range of limitation is narrow or wide depends on many elements. There is no real freedom, there is only an optimum limit of its own subject. Only when touching a limit, awareness about freedom really explodes and make people think.
The upside-down cage is a visual symbol to visualize the limit of limitation, which can be seen and touched. It could be broken, but also very flexible to limit living space of a subject in a way that it does not have to make the subject completely paralyzed.
From outside or above, we can see clearly the line of limitation. If from inside, only active subjects or persons with equipment can feel the limitation. Bamboo cage does not exist long in nature; if there is no strong impact, it will go under self-destroy process by sun and rains after times. Generally looking, if there is no severe conflicts from inside and outside right at the borders of the cage, everything seems to be very fine.