Removing Loops from LDPC Codes
An angulated indicator lens secured to the top portion of a relay valve for providing maximum refraction and dispersion of the several indicating colors on the valve stem indicating the operative or inoperative position of the valve. The lens is constructed of a unitary transparent body having an interior angulated, truncated surface of approximately 45 DEG to the horizontal, with an exterior angulated, truncated upper viewing surface of approximately 54 DEG to the vertical. The transparent lens body receives ambient colored light from the stem providing the maximum refraction of light onto the first interior angulated surface and directing the color to be indicated through the lens medium and onto the second exterior angulated truncated surface for maximum indicating area. A portion of the lens body is provided which is totally non-reflective and serves to shade the reflecting of that coloration of the valve stem which is not being indicating in order to avoid misreading of the valve as the valve shifts from an opened to a closed position. Distinctive markings are also included for indicating through the lens the operative or inoperative position of the stem for the color blind.