One of my coworkers, I'll call him Bob, has recently had to ask a roommate to move out over non-payment of rent. He's been searching for another roommate and is concerned that he'll have trouble finding one who is receptive to living with a musician. After doing a bit of searching, he located someone who wasn't interested, but recommended a friend who had a musician friend who was also looking for a roommate. Bob called the referral and discovered that the "musician friend" was Bob. He wound up being referred back to himself.