The doors are hinged along one side to allow the door to pivot away from the doorway in one direction but not in the other. the axis of rotation is not in the plane of the door to reduce the space required on the side to which the door opens. This is sometimes the case in trains, such as for the door to the toilet, which opens inward. An ideal way to have easy access to the garden, terrace, patio or relaxation area, hinged door is both versatile and functional.