We've featured doodling, fast-talking YouTube mathematician Vi Hart a lot here, but her latest, a 30-minute extended mix, is absolutely remarkable, even by her high standards. For 30 glorious minutes, Ms Hart explores the nature of randomness and pattern, using Stravinsky's 12-tone music as a starting-point and rocketing through constellations, the nature of reality, Borges's library, and more. On the way, she ends up with a good working definition of creativity, and explores the dilemma of structure versus creation. Brava, Ms Hart, you have outdone yourself! Plus, I like your copyright jokes.