http://www.stanford.edu/~laurik/fsmb...9;sPuzzle.html contains an interesting, systematic solution to it, but it's a fun puzzle. Anyone who hasn't tried it before should do so, before looking up the answer.

Those times are pretty quick.

"Stephen Wolfram is the creator of Mathematica and is widely regarded as the most important innovator in scientific and technical computing today." - Stephen Wolfram