A program should be the simplest program that meets the current requirements. The team puts a simple system into production early, and updates it frequently on a very short cycle. The team integrates the system every few hours. Each time, the system is built from scratch, and all tests run successfully. The acceptance tests are automated, and all must run successfully.
All code belongs to all programmers.
When something needs changing, any programmer can change it without delay. The programmers follow a common coding standard. Pair programmers work at computers in the center of the room.