[rickyplouis]

Slightly tangential, but in Brave New World they trained future embryos to be rocket-plane engineers altering oxygen levels based on their vertical orientation.

> The first of a batch of two hundred and fifty embyronic rocket-place engineers was just passing the eleven hundred metre mark on Rack 3. A special mechanism kept their containers in constant rotation. "To improve their sense of balance," Mr. Foster explained. "Doing repairs on the outside of a rocket in mid-air is a ticklish job. We slacken off the circulation when they're right way up, so that they're half starved, and double the flow of surrogate when they're upside down. They learn to associate topsy-turvydom with well-being; in fact, they're only truly happy when they're standing on their heads."