Finiteness of chain-code picture languages on the triangular grid

Chain-code picture systems are Lindenmayer-systems over special alphabets. The generated words are interpreted as chain-code pictures containing vertices and edges of the regular triangular grid. The finiteness of various chain-code picture languages are investigated based on properties of length-contracting, length-constant and length-expanding sD0L parallel rewriting systems. The case of shuffled axioms is also explored.