Stella has a fishpond in her backyard to which she retreats on occasion, for the pond has an island in the middle with a comfy wicker chair--perfect for when she wants to be alone. The pond and the island are square, as in the figure, so the pond makes a moat 64 inches wide around the island. To get to her sanctuary, Stella builds a bridge to the island out of two boards 63 inches long and 4 inches wide. When she is on the island she pulls the bridge up, producing the desired sense of isolation. How does she do it?

Hint: The width of the boards is irrelevant.