Fred and George were wearing blue sweaters, one with a large yellow F on it, the other a G.
"Harry's is better than ours, though," said Fred, holding up Harry's sweater. "She obviously makes more of an effort if you're not family."
"Why aren't you wearing yours, Ron?" George demanded. "Come on, get it on, they're lovely and warm."
"I hate maroon," Ron moaned halfheartedly as he pulled it over his head.
"You haven't got a letter on yours," George observed. "I suppose she thinks you don't forget your name. But we're not stupid -- we know we're called Gred and Forge."

Harry Potter and the Philosopher's Stone - Chapter 12 : The Mirror of Erised
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