Planning, testing, programming, and releasing are four elements of ExtremeProgramming that are encountered and exercised in increments. As each new DailyBuild or IncrementalRelease? is accomplished, the elements are repeated.
KentBeck lists TheFourElements as Coding, Testing, Listening, Design.
Internet References:
http://www.pearsonptg.com/book_detail/0,3771,0201733978,00.html
See