(= (Orientation (Reference-Frame Planar-Mace) (Reference-Frame Ground)) (Simple-Rotation 3 (Alpha Planar-Mace))) (<- (X ?X) (Dot (Position (Reference-Point ?X) (Reference-Point Ground)) (Basis.Vec (Reference-Frame Ground) 1))) (<- (Y ?X) (Dot (Position (Reference-Point ?X) (Reference-Point Ground)) (Basis.Vec (Reference-Frame Ground) 2)))