im 3,716,710 [45] Feb. 13,1973
A lamp comprising an elongated light source, such as a rod-shaped fluorescent lamp, and a lamp shade of transparent material. The lamp shade has its surface provided with a first set of grooves defining ridged elevations between them and extending parallel to the axis of the elongated light source, and two sets of diagonal grooves symmetrically crossing said first set of grooves in such a manner that the vertex lines defining the bottoms of the troughs formed by the diagonal grooves intersect on the lines of the ridges between neighboring longitudinal grooves and thereby divide the surface into panels of which each contains a prismatic center configuration having a face on each side of a longitudinal ridge, two quarter faces divided by a hip at each end of the ridge and a triangular base pyramid adjoining the foot of the face on each side of the ridge.
9 Claims, 23 Drawing Figures
