From: The World In Your Head by Steven Lehar

Fig. 8.3 (A) A periodic banded pattern revealed by chemical staining emerges in a developing embryo, due to a chemical harmonic resonance whose standing waves mark the embryonic tissue for future growth. (B) This chemical harmonic resonance has been identified as the mechanism behind the formation of patterns in animal skins, as well as for the periodicity of the vertebrae of vertebrates, the bilateral symmetry of the body plan, and the periodicity of the bones in the limbs and fingers. (C) Murray (1988) showed the connection between chemical and vibrational standing waves by replicating the patterns of leopard spots and zebra stripes in the standing-wave resonances in a vibrating steel sheet cut in the form of an animal skin.