Just published the Chemical concrete machine on figshare. Should be cited as
The description is a bit more telling than the abstract of the article (see why by reading the suggested posts below):
This article introduces an artificial, algorithmic chemistry based on local graph rewrites applied to a class of trivalent graphs named molecules. The graph rewrites are seen as chemical reactions with enzymes. The enzymes are tagged with the name of the respective move. This artificial chemistry is Turing complete, because it allows the implementation of untyped lambda calculus with beta reduction (but without eta reduction). This opens the possibility to use this artificial chemistry for constructing artificial chemical connectomes.
Here, on this open notebook/blog, you may read more about this here:
The article is available also as arXiv:1309.6914 [cs.FL].