Microlenses are fabricated with a refractive-index gradient. A DC voltage having an AC voltage superimposed thereon is applied to the capacitor and the DC voltage is swept between a first voltage and a second voltage. The lighting effect forms a position marking of the load handling device on the roadway which will be reached by the load handling device for a particular steering angle after the industrial truck travels around a curve by a defined curve angle. A flywheel, less than 1% of the vehicle weight, is coupled to the generator to store kinetic energy of the vehicle during decelerations. A stamp is drivable by a hammer cylinder for compressing said metal insert to shape and deform it into a tight fit with the via hole. Each of the opposing sidewalls includes at least one low section so that a human limb can be extended out of the cavity to maneuver the stretcher.