1- Child of uncle (father's brother) and of half-aunt (mother's half-sister) at the same time.
2- Child of uncle (mother's brother) and of half-aunt (father's half-sister) at the same time.
3- Child of aunt (father's sister) and of half-uncle (mother's half-brother) at the same time.
4- Child of aunt (mother's sister) and of half-uncle (father's half-brother) at the same time.
5- Someone who, in relation to others, has zero parents and three grandparents in common.
Irregular-double-first-cousin.