L-Systems Viruses and Symmetry-Step Procedures for Enhancing Fractal Computer Graphics.

This paper proposes two methods to obtain new highly aesthetic fractal computer graphics, by exploiting the genetic code-like structure of L-systems, and defining new different operations on it. We first select a family of L-systems, which shares the set of variables and constants in their L-system encoding system. After this initial selection, the first method proposed consists of a symmetry-step procedure in L-systems. It is based on a previous step of recombination or mutation in the expanded code of the L-system, followed by a concatenation of the resulting sequence. We show that enough concatenations of the expanded L-system sequence lead to symmetry in the final fractal graph obtained. When applied, this approach produces aesthetic fractals, comparable to those obtained after an evolutionary search, within just a fraction of the computational time. The second method proposed in this paper consists of introducing L-systems viruses in the expanded code of L-systems. An L-system virus is an exogenous code, artificially created or from other L-systems, usually of small size, which is introduced in the L-system main code at a given location, and modifies the final aspect of the fractal produced when it is interpreted by the L-system decoder. These two proposals have been used to obtain new fractal structures, with aesthetic properties. We also discuss further potential applications of both proposed methods in design problems using L-systems.