An apparatus for attachment to the body of a vehicle which has a front, rear and opposite sides and which has steerable wheels. For example, if a program transform alters one entity the constraint will provide the machinery to assure a compensating alteration of the other entities. The light fixture includes a housing having an open end and a wall visible through the open end, the wall defining an aperture having a size sufficient for determining whether insulation is within a predetermined distance of the light fixture. The second layer comprises at least one third region applied on the first layer, the third region having a density lower than the density of the first region. Regarding the battery pack, the end portion of the first battery is inserted inside the side wall of the connector in a non-contact state, and the bottom portion is welded to the first and second batteries, thus the first and second batteries being mutually coupled by the connector.