In one common pattern of pairing, one engineer fills the role of the driver , the person who actually writes the code, while the other engineer acts as the navigator, observer, or pointer , the person who reviews the work as it is being performed.
— The DevOps Handbook, in “18: Create Review and Coordination Processes to Increase Quality of Our Current Work”, Gene Kim, Jez Humble, Patrick Debois, John Willis & Nicole Forsgren