This is a story I've been trying to find for years. A scientist has built some sort of computer that is a vat of liquid chemicals. It automatically evolves programs by growing conductive veins through the vat of liquid. The basis of how it worked was basic chemical reactions and physics, that is, by "evolution" I mean some sort of selective trial and error process, and by "grow" I'm just referring to a chemical reaction where something accumulates. Think of a beaker in a chemistry lab with a few wires going in for inputs.
As a warning, this may or may not have been a fictional story. For a long time I thought it was non-fiction but recently I'm thinking it might have been some sort of hard sci-fi I read. Hopefully it was at least one or the other and not a dream I had.
This was in English, I believe it was something I read but it could have also been radio, my memory of it is more than 3 years old, probably more than 5 years old, but less than 10 years old.