Recall from Opening the Door that adding a complex number to another number is the same as a translation.
Recall from Into the Wilderness that multiplying a complex number by another is the same as a rotation and an enlargement.
Since u+v=v+u and uv=vu, we can decide which complex number we want to 'transform'. For example, for u+v, we could start at u and apply a translation corresponding to v, or we could start at v and apply a translation corresponding to u.