On whose work are Leonardo 's notes based in The Vitruvian Man ?
In a 2008 TED talk , artist Siegfried Woldhek , based on Leonardo 's features in Andrea del Verrocchio 's bronze statue of " David " , proposed that Leonardo may have done three self-portraits : " Portrait of a Musician " , the " Vitruvian Man " and the aforementioned " Portrait of a man in red chalk " .