A cover for an aperture in a vehicle wall for a handbrake lever includes various elements. If the identification means respond, control means which operate a door lock from a door handle are transferred out of their inoperative position into an operative position. Optionally, growth factors are added to the culture medium. In the first mode the floating objects are displayed in an x-y plane based on the z-order stack. The second member can be detachable from the first member to permit a substitution of a different imprinted logo on the second member. The length of the floating gates and the thicknesses of the control gate lines can be made less than the minimum resolution element of the process by forming an etch mask of spacers.