Suppose you want to pair up your delegates. The usual way is that you just give a simple instruction such as “partner with the person on your left”. What if in another exercise you want to pair them up again but this time with a different partner? You probably need to give a different instruction and devise a new pattern. If you have many exercises to go through, perhaps in a multi-day course, it can quickly become confusing to come up with new patterns. The usual instruction at this point becomes “find a partner you have not worked with so far” with the inevitable inefficiency as people would spend some time figure out who to go to.
It makes sense to have an easy system to find new partners for different exercises. The method presented here will facilitate this process.