A scanning arm assembly for multi-directional mechanical scanning of a semiconductor wafer or other substrate to be implanted includes a pair of drive arms connected by two linkage arms to form a quadrilateral. The system generates the document using content elements, which are created using the compiled data, and embeds the content elements into the document. The conditions define the breadth or narrowness of the subset of images from which a random element is chosen. The limit line is set substantially along an outer periphery of the obstacle at a position spaced a predetermined distance from the obstacle outward of the obstacle.