Light Step never did make Twilight the coffee maker she promised. Instead, she took the money from her art, and commissioned a book. She drew the cover herself.
It was a biography of Twilight, written like it was a novel. It began thusly:
Once upon a time there was a pony named Twilight Sparkle, who was eternally young. She had no use for her years, and where other ponies hoarded them, she gave them up freely.
But sometimes, when she was feeling sentimental, she’d go look at the years she left behind. She kept them in a book in her library, with a little yellow sticky note on the cover.
When she opened the book she could remember all the ponies she helped. She forgot them again as soon as she shut the cover. But they never forgot her.