A method for optically scanning and measuring an environment by means of a hand-held scanner for producing 3D-scans is provided. Conductive lines for the 3D memory array, and contact pads for vertical connectors used for couple the array to decoding circuitry and the like, are formed as parts of the same patterned level of material. The composition for flame-retardant flexible polyurethane foam of the present invention can give a flexible polyurethane foam that has satisfactory flame retardant properties, as well as excellent properties such as better heat resistance, fogging resistance and scorch resistance and extremely low compression strain. The frictional braking device is controlled so as to achieve the target braking force of another wheel, different from the wheel having the smallest target braking force, in cooperation with the regenerative braking device.