There was an episode of "Outer Limits" called "The Sixth Finger" that started a very young David McCallum. He advanced evolution on himself and got a big brain and six fingers on each hand. At one point in the show, he says that having six fingers makes it easier mathematically for him to play the piano. Almost 60 years ago, and I still remember it.
Probably keyboards as well.
There was an episode of "Outer Limits" called "The Sixth Finger" that started a very young David McCallum. He advanced evolution on himself and got a big brain and six fingers on each hand. At one point in the show, he says that having six fingers makes it easier mathematically for him to play the piano. Almost 60 years ago, and I still remember it.