An alphabet of shapes and a vocabulary of configurations.
Why are some forms more aesthetically pleasing than others? Is it just the symmetry that appeals to the mind or are there other elements of form that draw attention and engagement? Is it an underlying mathematical pattern that the mind can intuit? And if there is, why would the mind of a ground dwelling primate be interested? Music composed without words can communicate feeling, and the tone and pace of an unknown, spoken language can still communicate mood and urgency. Do the shapes of nature carry a message or am I just talking to myself?