Future

In 2910, 500 trillion live in a global city, 100 floors deep.
They only abundant resource is people. Carbohydrates, converted into food, fuel, materials, goods.

Sally unplugged VR school. A message commanded her to processing. Scared, she let herself be sucked up by the pneumatic transporter tube.
"please not fuel..." she thought, and was placed along 20 children who failed the same exam.
She watched nanobots convert their body matter into things more useful. A boy moaned as his chest turned into a computer console. Then his head became a screen.

Sallys skin felt rubbery. She turned into a tire.