Within recent years architects in virtually all countries of the world have shown great interest in the possibilities for using stained glass to enhance the beauty of concrete buildings. Today there are many examples of the handsome effects that can be created by the use of stained glass. While scientific advances in the ancient art of glass making have helped improve the esthetics of modern stained glass construction, the renaissance has, in reality, been possible only through the use of concrete to replace the traditional lead binding employed by medieval builders. The technique of retaining stained glass in place with H-shaped lead beads has been used for almost 1,000 years, but concrete can perform the same function more economically and with greater durability. Concrete also provides more versatility in the overall design of a stained glass area. The artist can include a solid black area in the design in a way that is impossible with conventional lead framing. The shape and thickness of the concrete frame can also be varied within structural limitations. Similarly, cross sectional thickness can be varied to allow the inclusion of varying thicknesses of glass. A stained glass panel is built by first taking the full color design and converting it into an actual size tracing, using a grade of tracing paper or cloth. Each piece of glass of the desired color is then cut to shape over this tracing. To cast a panel, a form is built rigidly around the tracing. Reinforcement then is cut or shaped to follow the contours of the concrete webs and to provide the required degree of retention for the glass. When both the glass dalles and the reinforcement have been cut to size, the glass edges should be coated with jointing compound and the glass accurately positioned on the tracing. A dab of suitable adhesive is then applied to keep the glass in place on the tracing. Careful troweling can do much to spade the mix to a high degree of compaction, but subsequent mechanical vibration is desirable to ensure maximum bond and uniform distribution of the aggregate. External vibration will usually be most convenient; internal vibration is rarely possible, except for larger structural portions or solid areas. After normal curing, the formwork is removed and cleaned up and the tracing stripped away. The edges of the segments can be cleaned with hand scrapers. Final stage of production is to polish the exposed glass with a soft metal brush and damp sawdust to bring out the natural luster of the material.