Abstract: A prismatic lighting panel of very low weight (less than four ounces per square foot), high strength, and good optical characteristics includes a grid of depending thin ribs on one inch centers, and a web of microprisms between the ribs.

Abstract: A two-part binding system includes one or more bifurcated posts integrally extending from a clamping strip or member. The posts are inserted into one or more apertures in a stack of punched paper or other material and a second clamping strip having one or more integral or separate latching buttons inserted over and around the posts. Each button includes one or a pair of toothed pawls integrally hinged to a cross bar extending across a button aperture. The posts contain a series of transverse ratchets facing each other. As the second strip and its integral or snap-in latching button is manually pressed over the posts toward the first clamping strip, the teeth of the pawl teeth ratchet successively into the posts toward the base of the posts until the stack of paper is firmly grasped and the teeth mesh with a final transverse ratchet. At this position, the strips are bowed putting the edges of the stacked sheets in compression.