A mark forming method for a moving body is disclosed. In another aspect, the present invention kit can be seen as embodying a variety of optional modular components that can be used for constructing steps, landings, andor decks. The body further defines a crown that extends over the void. When confirmation is made about the fact that the person is authentic, the parameter is extracted from the total personal password to be judged. The protrusion defines a side wall. Further, the automatic-clutch control system decreases an engagement force of the automatic clutch according to an increase of the deceleration and a decrease of a vehicle speed to vary the engagement state.