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The folklore surrounding pianist Ignace Pederewski includes this story. A mother, wishing to encourage her son's progress at the piano, bought tickets for a Pederewski performance.
They had seats near the front of the concert hall.
The mother found a friend to talk to and the boy slipped away. When eight o'clock came around, the spotlights came on, and only then did they notice the boy at the piano bench innocently picking out "Twinkle, twinkle little star."
The master appeared on the stage and quickly moved to the keyboard.