Also known as writer's block, this is a common phenomenon for people involved in the creative arts. Do notice though, that this is common only to a situation whereby a person has the free time to create under no sense of urgency. What I mean here is that in the performing arts--theater, live music, live performance in general--an artist doesn't have the luxury to be so blocked that they cannot perform. In a word, the show must go on. That right there might give you a little hint about the so-called writer's block phenomenon.
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https://www.youtube.com/watch?v=1fWjx8hKRc0
Emma Barret hula-hooping to the tune of Break On Through and Secret Agent Man at the closing party for Danny's Deli in Venice, CA,
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https://www.youtube.com/watch?v=kRUeZxufuyk
As a composer, I have a bad habit of writing pieces that stand at the precipice of my technical skill. This one has always been very difficult for me to play. That's why I call it 'A Wing & A Prayer,' because that's exactly how it feels when I attempt playing this one. This was absolutely pre-composed when I was living in Austin, TX in the mid Nineties. I'm proud of this piece as a real work of art.
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https://www.youtube.com/watch?v=3RENaDAYG9M
I've created a new playlist for Pentatonic Theory although it's not quite a "system" unto itself. Yet, it deserves special attention.
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https://www.youtube.com/watch?v=9mndQtHUWKA