I knew a couple in college that had two kids. I believe the wife took the husband’s last name. His name was something like Frer Thorson, and the wife’s name was Inga Thorson.
Their little boy was Thor Frerson, and the daughter was something Ingandaughter (or however one spells daughter in Iceland - dotter?) Pretty confusing.
the Russians do something similar, with your middle name being derived from your parent’s first name, but with last names being inherited from the father.