[cesaref]

Just found reference to it on David May's page, which is suitably retro html for the Inmos architect who created occam and did all sorts of interesting things like formally prove their FPU implementation (before formal proofs for that sort of thing were common):

http://people.cs.bris.ac.uk/~dave/transputer.html

'The B0042 board contains 42 transputers connected via their links into a 2-dimensional array. A number of them were built following a manufacturing error - all of these transputers were inserted into the packages in the wrong orientation so were fully functional but unsaleable. I had them all (around 2000) written off for engineering use and we built the B0042 'evaluation' boards! Many of these were given to Southampton University where they were assembled into a 1260 processor machine and used for experimental scientific computing. Inmos used them in a number of exhibitions (in a box of 10 boards - 420 processors) drawing Mandelbrot sets in real time!'

Sounds like the machine I remember, a 420 processor machine in a box in the late 80s was quite something.