The six educated
frogs in the illustration are
trained to reverse their order, so that their numbers shall read 6, 5,
4, 3, 2, 1, with the blank square in its present position.
jump to the next square (if vacant) or leap over one frog to the next
square beyond (if vacant), just as we move in the game of draughts, and
can go backwards or forwards at pleasure.
Can you show how
their feat in the fewest possible moves?
It is quite easy,
so when you
have done it add a seventh frog to the right and try again.
more frogs until you are able to give the shortest solution for any
For it can always be done, with that single vacant square, no
matter how many frogs there are.