Nature delights in making use of the same forms in the most various biological connections: as it does, for instance, in the appearance of branch-like structures both in coral and in plants, and indeed in some forms of crystal and in certain chemical precipitates.

The Standard Edition of the Complete Psychological Works of Sigmund Freud: (1913-1914) Totem and taboo and other works. [1955 (ed. 1953)