““So we’re surrounded by absolutely nothing,” said Rincewind. “Total nothing.” He hesitated. “There’s a word for it,” he said. “It’s what you get when there’s nothing left and everything’s been used up.” “Yes. I think it’s called the bill,” said Eric. Rincewind gave this some thought. It sounded about right. “Okay,” he said. “The bill. That’s where we are. Floating in absolute bill. Total, complete, rock-hard bill.””