Abstract: A generalized, machine readable optical printed symbol format for the representation of a plurality of codes, each symbol requiring minimal space, thus permitting a greater packing density. The optical printed symbol format is generally hour-glass shaped and consists of nine elements, each of which is either a bar or a space alternately and each of which can be wide or narrow. Alternate bars and spaces are arranged vertically in a generally hour-glass configuration such that the length of the bars and spaces is greater at the top and bottom of the symbol and decreases to a minimum point at the middle of the symbol. Optical printed symbols using this shape can be read in forward and reverse and upside down. A wider skew angle between the optical printed symbol and the scanner allows greater tolerances than heretofore possible with a consequent diminishing of the error rate in machine scanning.