Here is an image that I lifted from a presentation (http://www.slideshare.net/KrisBuytaert/velocity2013-mh). I have written about this in the past so having this is a win.
Update: I came upon this (http://blog.8thlight.com/uncle-bob/2013/12/10/Thankyou-Kent.html) post today. It describes extreme programming some number of years later. What is amazing is that it's almost exactly the agile process.