Array Languages and Lindenmayer Systems —A Survey

In 1968 Lindenmayer introduced a mathematical model of developmental systems [28]. This involves parallel rewriting in which each letter in a string is rewritten using production rules and there is no distinction between terminal and nonterminal symbols reflecting the simultaneous growth of each cell during different stages of development. Since then L-systems have been studied extensively, resulting in the number of research papers growing exponentially [19,29,54,56]. An interesting comment from a referee is a pointer to the extent to which the theory had developed within a span of five years. In 1973 we submitted a paper entitled Parallel O-Lindenmayer Languages which we abbreviated as POL [69]. Then pat came the referee’s comment: “P already stands for ’propagating’ and almost all letters of the alphabet have been used up. You may try PaOL”.