Colin liked subtracting numbers from other numbers to create entirely new numbers. This is how he discovered 3158.
   He counted all the lights on a hillside on a winter afternoon and subtracted the number from the amount of birds on a telephone wire. This is how he found eight. He showed it to Chloe when the stars were coming out above. He tried to ignore those lights.
   She was impressed with his eight, but she said she could show him a nine. She took him to the local community hall, where a band were rehearsing on the stage. Her nine involved subtracting the band from some biscuits. He would have been impressed with this, but she had to eat some of the biscuits to get the nine.
   Halfway through the song, the band stopped. The lead singer, Greg, turned to the backing singer, Liz, and said, "You keep coming in at the wrong time."
   She said, "The only time you should start singing is after everyone has left the building."
   "If you can write some decent lyrics, you can sing them on your own. But all you come up with is songs about how to get an ostrich into a bikini."
   "I was making a comment."
   "Yeah, and a very useful one. Don't kiss an ostrich."
   "There was nothing about kissing an ostrich in it. What does that say about your mind if you listen to a song and the message you get from it is that you shouldn't kiss an ostrich?"
   "If I was listening to 'Wind Beneath My Wings' or 'Uptown Girl' and I got that message, then I'd say there was something wrong with my head, but I was listening to 'Miss Ostrich'."
   "Fine. I take back the suggestion that there's something wrong with your mind because that would imply that you have a mind. There are birds nesting in your head because they found a hollow space there and they've blocked off your ears because they can't stand the sound that comes from your mouth, and they've blocked your nose as well, and that's why you smell."
   "Every day I thank God I have those birds in my head and not that bloody ostrich."
   This was the point at which Liz announced her departure from the band. Colin and Chloe were left with a ten. Chloe could have eaten another biscuit, but this would have felt like cheating. They went outside and tried to convince Liz to return to the band.
   They had to go back and forth between Liz and Greg as they tried to resolve the dispute. Liz had many issues. She wanted to be closer to the front, or do a dance, or at least sneeze. And Greg had banned her from talking to the audience after the time the guitarist had to change a string on his guitar, and she passed the time by telling the audience about her theory that when people play tennis they're just throwing lemons at each other. She wanted to be able to talk to the audience too.
   Greg agreed that she should be allowed talk to the audience between songs, and he let her stand closer to the front, but further to the side. Liz was still unsure about returning, so Chloe gave her the biscuits to swing the deal.
   She joined the rest of the band on the stage, and they started playing again. As she was waiting for her part, she ate a biscuit. At first Colin and Chloe tried to stop her, and then they tried to convince her to leave the band again, but they gave up when she ate another biscuit.
   "Let's go to the shop and get some more biscuits," Chloe said.