Symmetry and periodicity manifest themselves throughout all of human aesthetics, not just in decorative art, ornament, and architecture, but also in music, rhythm, poetry, and dance, that express periodicity and symmetry across time as well as space.

The alien visitor, on seeing these kinds of patterns throughout human aesthetics, would immediately conclude that humans have harmonic resonance brains, that is, our brains operate by generating periodic and symmetric patterns of standing waves across the neural tissue, and those standing waves are the principle by which spatial structure is represented and experienced in the brain.