FAIL?
While it's true there's no fancy techniques being used, that wasn't the spirit of the original problem either, and yes the synchronisation make it somewhat of a mule, it's also important to remember, that there's no such thing as a "stupid publicity stunt" - it's being reported and talked about, so it's a "successful publicity stunt".
That said, lets talk about what could have been done, the Specy *can* do polyphonic (after a fashion), the most well known engine for this is "ZX-7 Polyphonic" so in theory you could do this with two, in which case a crossover serial type sync would be all you need - perhaps you would think that's more of an authentic solution.
However! if there was no Pi, no network, no collection of retro computers, would that have got publicity? would we be talking about it? Perhaps not - but until you do something vaguely interesting - hell! get a couple of Spectrum's and do it like I suggested above, then perhaps you'll have a more valid opinion.
Biting the hand that feeds IT
