func (v Vec3) Cross(v1 Vec3) Vec3 {
	return Vec3{
		v[1]*v1[2] - v[2]*v1[1],
		v[2]*v1[0] - v[0]*v1[2],
		v[0]*v1[1] - v[1]*v1[0],
	}
}
func (v Vec3) Cross(v1 Vec3) Vec3 {
	return Vec3{
		v[1]*v1[2] - v[2]*v1[1],
		v[2]*v1[0] - v[0]*v1[2],
		v[0]*v1[1] - v[1]*v1[0],
	}
}
// Cross returns the cross product of two vectors. v x v1