yacc (compiler generator), 1104

Yang–Mills theories, 1045, 1057
instanton solutions to, 1133

Yemen
nested drainage pattern in, 1187

Yin and yang
and substitution systems, 893

Young, David A. (USA, 1942– )
and pigmentation patterns, 1012

Young, Thomas (England, 1773–1829)
and color vision, 1075