The lead designer and two to seven other developers in a large room or adjacent rooms, with information radiators such as whiteboards and flip charts on the wall, having access to key users, distractions kept away, delivering running, tested, usable code every month or two (okay, three at the most), periodically reflecting and adjusting on their working style.
— Alistair Paul Becker, Alistair Cockburn, Crystal Clear: A Human-Powered Methodology for Small Teams, 2004