The diagrams show four fundamentally different solutions. In the case of
A we can reverse the order, so that the single dog is in the bottom row
and the other four shifted up two squares. Also we may use the next
column to the right and both of the two central horizontal rows. Thus A
gives 8 solutions. Then B may be reversed and placed in either diagonal,
giving 4 solutions. Similarly C will give 4 solutions. The line in D
being symmetrical, its reversal will not be different, but it may be
disposed in 4 different directions. We thus have in all 20 different
solutions.
[Illustration]