I’ll listen to a single song, over and over on repeat, like a hundred times. And I turn off instant message and e-mail. If you are taken out of the flow, if that little toaster pops up that says you’ve got mail — and you look at it, you’ve lost it. You’re juggling variables and functions and layouts. The moment you look away, it all falls to the ground, and you spend 10 minutes getting it all back in the air again.