Hello, I was wondering how I could express a geometric quantity which has only magnitude and direction but no orientation (sense)? and perform ordinary operation on that. For example: it is clear that a vector is not appropriate because vectors with same magnitude-direction but opposite orientation will cancel out: instead I want that two entities with same magnitude and direction will result in another entity with the same direction and double magnitude. Is this possible to do? I've heard somewhere that this is probably done using tensors, but I have no idea how. Maybe I misunderstood. Any idea?