"Chemlambda is a graph rewriting system derived from graphic lambda calculus which can be seen as a simple model of chemical or biological computing."

here are demonstrations of the graph rewrite rules:

http://chorasimilarity.github.io/chemlambda-gui/dynamic/move...

the front page is a better start: http://chorasimilarity.github.io/chemlambda-gui/index.html

as is the FAQ: https://chorasimilarity.wordpress.com/2015/02/19/what-can-i-...