There seems to be something deeply effective about setting arbitrary constraints. Obvious examples abound: haiku, twitter, 80-char code, screenplays in fixed-width Courier, 25-minute pomodoro, text-only man pages. Also, the metronome of practicing music (cadenzas don't count), the fixed 8 hour workday, the 12-tone music temperament..<p>I've wondered what a piece of software could look like with each function/codeblock written on 1 index card each. Linus seems to prefer one-page functions for C, but I like the extreme of the index card.