Cast glass is a molded or textured glass manufactured by using one of three different methods. Sometimes called slumped glass or kiln formed glass, it is made by placing float glass in a kiln over top of a mold with the desired pattern embossed into it. The glass is heated to it’s softening point where it slumps into the shape of the mold. It is then annealed and can be further fabricated. https://morethanglass.com/products/cast-glass.html