Henry Ernest Dudeney/Puzzles and Curious Problems/260 - Stepping Stones/Solution

Puzzles and Curious Problems by Henry Ernest Dudeney: $260$

The diagram represents eight stepping-stones across a stream.

The puzzle is to start from the lower bank and land twice on the upper bank (stopping there),

having returned once to the lower bank.

But you must be careful to use each stepping-stone the same number of times.

In how few steps can you make the crossing?

Number the stones as follows:

Then go:

$1$, $(\text {bank})$, $1$, $2$, $3$, $(2)$, $3$, $4$, $5$, $(4)$, $5$, $6$, $7$, $(6)$, $7$, $8$, $\text {bank}$, $(8)$, $\text {bank}$

which takes $19$ steps.

Those in brackets are backward steps.