Black holes are pretty scary when you ponder them. They seem nihilistic, infinitely destructive on an inconceivable scale, notwithstanding the ideas of Hawking radiation.
I remember from my school days Archimedes jumping into his bath and displacing water and coming up with his famous principle, and of course Isaac Newton being hit on the head with an apple. In other words, this realm of human knowledge - which is mathematical, essentially - can have a playful visual element to it.
