There's a planet,' said Spike, 'made of water, entirely of water, where every solid thing is its watery equivalent. There are no seas because there is no land. There are no rivers because there are no banks. There is no thirst because there is no dry. 'The planet is like a bowl of water except that there is no bowl. It hangs in space as a drop of water hangs from a leaf, except that there is no leaf. It cannot exist, and yet it does. I tell you this so you know that what is impossible sometimes happens.