I'm not sure what ben_jones had in mind, but we've been doing a lot of pairing and mob programming where I work. I really enjoy it and it feels like the code review is basically just being done at all times (the reviewer is sitting right next to you as you write). But others feel like it eliminates some of the advantages of parallelism (i.e. 2 people working on 2 different things). It also slows down the amount of time to complete stories if one developer is less skilled than the other, but that issue should fade with time.