Shh!" said Ford. "It's conical. So what you do is, you see, you fill it with fine white sand, alright? Or sugar. Fine white sand, and/or sugar. Anything. Doesn't matter. Sugar's fine. And when it's full, you pull the plug out... are you listening?" "I'm listening." "You pull the plug out, and it all just twirls away, twirls away you see, out of the plughole. "Clever." "That's not the clever bit. This is the clever bit, I remember now that this is the clever bit. The clever bit is that you then thread the film in the projector... backwards!" "Backwards?" "Yes. Threading it backwards is definitely the clever bit. So then, you just sit and watch it, and everything just appears to spiral upwards out of the plughole and fill the bath. See?" "And that's how the Universe began is it?" said Arthur. "No," said Ford, "but it's a marvelous way to relax.