"Yes, that's right."

"The wires go out from the cave and fence in a
circle of level ground a hundred yards in diameter;
they make twelve independent fences, ten feet apart --
that is to say, twelve circles within circles -- and their
ends come into the cave again."

"Right; go on."

"The fences are fastened to heavy oaken posts only
three feet apart, and these posts are sunk five feet in
the ground."

"That is good and strong."