A removable and attachable debris guard for a back wall of a loader bucket or a bulldozer blade is provided with a frame that is a generally inverted U-shape with outwardly tapering side legs, and has a strong mesh screen supported on the frame. The elevator system comprises two elevator shafts constructed adjacent to each other. The method also includes the steps of storing at least a subset of the plurality of data values in a memory and computing a plurality of texture coordinates of the geometry from a projective transformation corresponding to the selected perspective. The direction of the channel current controls which floating gate receives channel hot electron injection during programming and which floating gate state is sensed during reading. The selector is operable on a per-shift basis in transparent mode wherein data is supplied to all input lines and several direct modes wherein data from only one scan chain is supplied at each compressor output without overlap.