MB has it right, the bees fan the nasanov to orientate the nurse bees who have never been outside of the hive so that can get back to the right hive. When working the bee yard you can look back at all the hives yolu've inspect, the cloud of bees in the air resembling a swarm, and the bees on the landing boards, butts to the sky, telling all the young bees that went airborne during the inspections to come home.
However, I messed with their minds today. I went into three hives, taking 2 frames from each hive, and made 2 splits using some SMR Russian Queens from Wilderness Apiaries. That puts bees and brood from 2 different hives in the same box. On the 4th hive I changed it from a 2 story nuck box to a 2 story 8 frame medium. The air looked like a real swarm. I now have 6 hives counting the 2 new nucs.