Algorithms and information, fundamental to technological and biological organization, are also an essential aspect of many elementary physical phenomena, such as molecular self-assembly. Here we report the molecular realization, using two-dimensional self-assembly of DNA tiles, of a cellular automaton whose update rule computes the binary function XOR and thus fabricates a fractal pattern--a Si...

Sstarting from a set of strands (or other types of building blocks) a variant of forbidding-enforcing systems for graphs is proposed which models the DNA self-assembly process. The possible outcomes of the self-assembly process comply with necessary constraints arising from the physical and chemical properties of DNA. A set of forbidding and enforcing rules that describe these constraints are p...