"Vector numbers" for something purely 2D seems dodgy to me. There are lots of unital algebras, even in 2 and 4 dimensions, and none of them should hog the name

"Vector numbers" for something purely 2D seems dodgy to me. There are lots of unital algebras, even in 2 and 4 dimensions, and none of them should hog the name "vector numbers" as they all have equal entitlement to the name.