In the illustration
the matches represent hurdles and the
coins/counters are sheep.
The sixteen hurdles on the outside, and the sheep, must
be regarded as immovable; the puzzle has to do entirely with the nine
hurdles on the inside.
hurdles enclose four groups of 8, 3, 3, and 2 sheep.
requires to readjust some of the hurdles so as to enclose 6, 6, and 4
Can you do it by
only replacing two hurdles?
When you have
succeeded, then try to do it by replacing three hurdles; then four,
five, six, and seven in succession.
Of course, the hurdles must be
legitimately laid on the dotted lines, and no such tricks are allowed
as leaving unconnected ends of hurdles, or two hurdles placed side by
side, or merely making hurdles change places.