A reusable stair cover is described having a length of washable material for covering a number of stair treads and intervening risers. The hole is not located on a first half-line extending from the gravity center of the hole, while the hole is located on a second half-line extending in the direction opposite to the first half-line. The operational amplifier corrects the difference in the temperature coefficients of these currents to output a voltage of ground electric potential standard. The method also includes determining motion information associated with the video element. Inter-level dielectric mask is then deposited, contact holes etched, and contact metal is deposited to form the transistor.