Johan de Boer's description (from private correspondence 2010)
"A second project [ RH: to the Cybernetic Mouse] was the maze where a light was used to indicate the position of an imaginary mouse in the maze. The maze could be changed with small removable barriers. Each square had a small light bulb that would be on if the (imaginary) mouse would be in that square. This whole thing was a cube with sides of about 20 cm. Unfortunately there is no photo and this thing was lost (or scavaged, possibly).
This maze/mouse was controlled with a small especially designed and build computer. This was about 1970-1973. I still have the computer (two photos are attached), and I recently discovered that I still have the schematics for the computer (see pdf here). It was build with about 100 of the 74 series chips, set on 5 circuitboards with an aweful lot of wiring. It has a 1kb (kilobit, not kilobyte) memory chip into which a total of 64 instructions could be loaded. This would run programs at a speed of at most 200 instructions per second (illustrates my electronics skills, I guess). It would query the condition of the maze and sent instructions to the maze in order to change the light bulb that was illuminated. I could then alter the programming in order to come up with something that would learn its way through the maze. The computer, of course was a general purpose machine that could be used to control anything, even an elaborate electric trainset, I would think. "
(*-Johan de Boer currently lives in Canada.)