public function add($x, $y = 0, $z = 0)
{
if ($x instanceof Vector3) {
return new Position($this->x + $x->x, $this->y + $x->y, $this->z + $x->z, $this->level);
} else {
return new Position($this->x + $x, $this->y + $y, $this->z + $z, $this->level);
}
}