Are we allowed to use negative boolean operations like, for instance, creating a half-sphere by subtracting a parallelepiped from it or creating a parallelepiped with a cut corner by subtracting another parallelepiped from it, both cases using up 2 shapes towards the shape count? Here, you mention cutting shapes is allowed as long as they are merged together, so could negative boolean operations possibly be allowed as long as they do not split the shape into multiple (the result is still connected)?