Hipnopædia

At the end of the room a loud-speaker projected from the wall. The Director walked up to it and pressed a switch.
'...all wear green', said a soft but very distinct voice, beginning in the middle of a sentence, 'and Delta children wear khaki. Oh no, I don't want to play with Delta children. And Epsilons are still worse. They're too stupid to be able to read or write. Besides, they wear black, which is such a beastly colour. I'm so glad I'm a Beta.'
There was a pause; then the voice began again.
'Alpha children wear grey. They work much harder than we do, because they're so frightfully clever. I'm really awfully glad I'm a Beta, because I don't work so hard. And then we are much better than the Gammas and Deltas. Gammas are stupid. They all wear green, and Delta children wear khaki. Oh no, I don't want to play with Delta children. And Epsilons are still worse. They're too stupid to be able...'
The Director pushed back the switch. The voice was silent. Only its thin ghost continued to mutter from beneath the eighty pillows.
'They'll have that repeated forty or fifty times more before they wake; then again on Thursday, and again on Saturday. A hundred and twenty times three times a week for thirty months. After which they go on to a more advanced lesson.'

Aldous Huxley, Brave New World; p.21. Longman Literature, 2002