Among other things, the present invention provides systems and methods for fulfilling reward redemptions. The substrate has a pixel area and a peripheral area adjacent to the pixel area. The optical pulse stretcher also has a plurality of beam splitters, each of which intercepts a portion of an input optical beam and diverts the portion into one of the plurality of optical cavities. A plurality of connecting members connect the apices of adjacent annular elements. The residence time of oil vapors ranges from about 0. After a pin passes through the positioning hole, a distal end of the pin exactly protrudes into the limiting groove.