sensors easy - reconfigurable logic tricky (Score 4, Interesting)

I'd like to know how he could have programmed responses like "fear of light" with a handful of discrete transistors.

Use two light sensors (such as light dependant resistors) to measure how much light the bug is in and to help guide the bug away from the light. When one sensor reaches a certain threshold, I imagine "move away from light" circuitry takes over and guides the bug towards darker areas with the light intensity information from the two light sensors - if the right sensor is darker, move right, if the left sensor is darker, move left.

What I'd like to know is, how they are implementing the downloadable transistor patterns. I know that reconfigurable digital logic can come in the form of Field Programmable Gate Arrays (FPGA) so I wondered if there was such a thing as Field Programmable Transistor Arrays (FPTA). Punched it into Google and hey presto NASA has a paper on an FPTA that JPL has developed!