Also very common for round the world tickets. I used to make several trips a year to Asia and Europe with multiple stops on the way, so RTW's were cheapest way to go.
Originating in Asia was/is much cheaper than originating in North America. So I would buy one starting in Seoul or Tokyo, make 4-5 stops in Asia, then a couple in Europe,
then back to North America for 4 months. Then resume the RTW back to Asia for the start of the next trip, and buy another to continue. Rinse and repeat.