Executive toys have been knocking around managers' desks for nigh on 30 years now, but one such device has lasted in popularity where others have been superseded by newer, shinier units. What are we talking about? The legendary Newton's Cradle.

If you've never seen one in action, simply lift and drop one of the balls at the end of the row, then watch in amazement as the ball at the other end leaps into the air. As it settles, the original ball will leap into the air. And so on and so on. Cool eh? Bound to provide some enjoyment and curiosity for a few minutes at least. Now try the same thing with two balls. Magic!

There is something oddly hypnotic about watching these steel balls collide with each other, simultaneously providing a soothingly and relaxing clicking. For busy executives, the Newton's Cradle provides a calming influence with it's metronomic soundtrack. Or a brilliant way of wasting time. The choice is yours.

So don't be fooled. The Newton's Cradle has nothing at all to do with beds for babies. And in reality, less to do with toys either. Because the Newton's Cradle is based on some fundamentally important laws of physics in order to work. Combining momentum and kinetic energy ( momentum (mass x velocity) and kinetic energy (0.5 x mass x velocity^2) if you must know), the Newton's Cradle is completely self-powered (apart from the bit where you lift and drop the first ball of course).

If you are looking for an executive toy which oozes class and history, you can't go wrong with the Newton's Cradle. Factor in the educational possibilities (apparently physics is sexy these days) and you have the ultimate desktop accessory available.