Precasting symmetrical or abstract designs with colorful handplaced tiles on a concrete panel might once have promised to be an unreasonably expensive endeavor. Recently, however, a way was developed to use vibrant color designs in permanent jobsite precast concrete structures with a revolutionary glass tile that can be used with great versatility. The new materials is not really tile but a hybrid form of glass and marble with characteristics of both. Glass is ground with marble, heated to a molten condition that fuses the materials, then poured into molds that resemble a waffle grid. The cooled mixture is broken apart at the surface, producing a three-fourths of an inch square about one-eighth of an inch thick. Because the color is fused into the body of the material, it has a nondeteriorating permanence, unlike the surface colors of ceramic or glazed tile. On the jobsite, there are several ways to go about casting glass tile in the concrete. A more popular one is called the "reverse method." In the "reverse method" of casting, the sheets of tile are temporarily pasted down in the mold. The latex cement is applied to the exposed tile with a trowel or brush. The mold is filled with concrete and set aside to dry. The paper on the face of the tile is simply pulled away after it has been soaked with water. Finally, the face of the casting is backgrouted with a sanded latex grout. In addition to the ease of application, this type of glass tiel features other advantages to jobsite precasting. With a sound, well cured concrete mix there is no danger of structural failure. Since each tile has mitered edges, a wedge shaped matrix is formed around each tile when concrete is poured against the back of it. This matrix is thick at the bottom and tapers to a hair line at the surface, gripping each tile in much the same way as a diamond is set in a ring. Another advantage is it is not necessary to use expensive molds required for smooth castings when working with glass tiles because it is impossible for grain marks and imperfections to telegraph through them. Hence, costly molds won't run up the cost of doing the job.