Glass that is made generally smaller and significantly thicker than traditional windows and look like building blocks are called glass blocks. They can be anywhere from 2- to 3-inches thick or more and they offer light transmittance but not usually the same optical clarity as regular windows. Glass blocks, which are sometimes called glass bricks, are often squares, though they can be made into other three-dimensional shapes, such as hexagons and end blocks for curves. Glass blocks are most frequently used in wall fabrications (especially bathroom installations) and decorative windows, though they can also be used in flooring and some furniture building.
Glass block
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