phase beauty

"A flowering spray of lily-of-the-valley exemplifies a growth gradient, after a simple fashion of its own. Along the stalk the growth-rate falls away; the florets are of descending age, from flower to bud; their graded differences of age lead to an exquisite gradation of size and form; the time-interval between one and another, or the "space-time relation" between them all, gives a peculiar beauty -- we may call it phase beauty - to the whole." 

(D'Arcy Thompson On Growth and Form, page unknown, quoted in Lindenmayer and Prusinkiewicz, "Developmental Models of Multicellular Organisms", Artificial Life 2, p.230) 

D'Arcy Thompson: "We might call the form of an organism an event in space-time, and not merely a configuration in space."