"I saw one made, only yesterday," the Earl replied. "Muriel, my child, were you not making one, to amuse those children you had to tea?"
"Yes, I know that Puzzle," said Lady Muriel. "The Ring has only one surface, and only one edge. It's very mysterious!"
"The bag is just like that, isn't it?" I suggested. "Is not the outer surface of one side of it continuous with the inner surface of the other side?"
"So it is!" she exclaimed. "Only it isn't a bag, just yet. How shall we fill up this opening, Mein Herr?"
"Thus!" said the old man impressively, taking the bag from her, and rising to his feet in the excitement of the explanation. "The edge of the opening consists of four handkerchief-edges, and you can trace it continuously, round and round the opening: down the right edge of one handkerchief, up the left edge of the other, and then down the left edge of the one, and up the right edge of the other!"
"So you can!" Lady Muriel murmured thoughtfully, leaning her head on her hand,
