public static Vector2 operator +(in Vector2 v1, in Vector2 v2) => new Vector2(v1.x + v2.x, v1.y + v2.y);
return(_square(v1.x - v2.x) + _square(v1.y - v2.y) +
internal static Vector3 Add(this Vector3 v1, in ReadonlyVector3Int v2) => new Vector3(v1.x + v2.X, v1.y + v2.Y, v1.z + v2.Z);