Elizabeth Goode and Dennis Pixton,
Semi-simple Splicing Systems (11/25/99) ( dvi or postscript or pdf)
in Where Mathematics, Computer Science, Linguistics and Biology Meet (C. Martin-Vide & V. Mitrana, eds.), Kluwer Academic Publishers, Dordrecht, 2001, pp. 343-352.

We present simple graphical tools for analyzing a generalization of simple splicing languages. Our semi-simple splicing languages are generated by rules of the form (a,1;b,1) where a and b are alphabet symbols. Our main result is that any such language is strictly locally testable.