Abstract: A window system has matching groups of window sashes which enable the creation of a great number of different window array patterns using modular, interchangeable sashes. The sashes have light-dividing mullions which intersect with the sash frame at a particular level or width point such that another sash when positioned adjacent to the sash will have its mullion or mullions positioned to continue the same mullion line through the two sashes. In preferred embodiments the sashes are all rectangular, some groups with linear mullions and some groups with diagonal, arcuate or elliptical mullions.

Abstract: A translucent end block which may be secured to an exposed side or top abutting surface of a translucent block includes a pair of parallel upper and lower surfaces spaced from each other and having generally the same preselected shape. A pair of side walls extend between the upper and lower surfaces and are joined to the upper and lower surfaces. The pair of side walls each have first wall portions positioned in parallel, spaced relation with each other and nonparallel second wall portions. A first end wall is positioned between the pair of side walls first wall portions and is joined to the upper and lower surfaces and to the pair of side walls first wall portions. The end block is secured to an exposed side or top abutting surface of a translucent block which forms a part of a translucent block wall structure to provide a translucent block wall structure having usable top or side surfaces.