There is definitely something else here... it is meta-irony, meta-statement, an allegorical image of people stuck in the cage of a metropolis and tall buildings... we are rats who are simply climbing up, our bodies are getting fatter under the weight of our ego and hedonism... stones are falling on our heads as a consequence of the price we paid for getting such a high place in the hierarchy... we walked on other people's heads and now we will get what we deserve - everything will end with a blow to a stone and we will fall... and lose weight, remembering that the body is just a shell of our lost thin soul