[metafunctor]

Probably “An evolved circuit, intrinsic in silicon, entwined with physics” [1]. They let a genetic algorithm come up with a better FPGA circuit, but it no longer worked when non-contributing parts of the circuit were pruned.

[1] http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.50....

[bayesian_horse]

And it didn't work in another FPGA chip of the same model.