The cello is a very fine instrument - just ask Yo-Yo Ma - but it has some fundamental weaknesses. The most obvious one is that there's no way to play more than two of its four strings simultaneously.

HE’S the same height as his cello and he often needs help carrying it, but that hasn’t stopped Jeremy Spikmans, 8, from being a superb cellist. But despite this minor problem, the eight-year-old is ...