"Soon as I finish," the old man answered. "Get pencil and paper. As I move knight from square to square, you draw."
Shrugging his shoulders slightly, but not so noticeably that the puzzle-maker could see, Eric obeyed. It seemed very silly to him. But as the knight went from square to square in the peculiar move which belongs to that piece in chess, the boy was amazed to find a wonderful and fascinating geometrical design growing under his hand.
"Another way, too," said the old man thoughtfully, the instant the figure was finished, not giving the boy a chance to make any comment. And, without further preface he started again. This time an even stranger but equally perfect design was formed.
"But that's great!" said Eric, "how do you know it's going to come out like that! I wonder if I could do it?"
"Try him," the puzzle-maker answered, getting up from the board. For half an hour Eric moved the knight about, but never got as perfect an example as the old man.
"Are there only those two ways?" said the boy at last.
"Over thirty-one million ways of moving the knight so that he occupies each square once," was the reply. "Every one makes a different design."
"I'll try some this evening," said the boy. "But it's funny, too. Why does it always make a regular design?"
"You want to know? Very well." And the puzzle-maker quietly explained some of the most famous mathematical problems of all time, working them out with the chessmen and the board.
"You know what they call him, magic?" queried the old man.