Generally windows that do not open or close are considered picture windows. They are designed to bring natural light indoors and to frame a beautiful view of the surrounding landscape, cityscape or even the sky.
Picture windows can be made in any shape: square, circle, rectangle, triangle, trapezoid, rhombus, or octagon. Multiple picture windows can be installed in the same wall, and often, they are joined with a narrow technique called mulling. Picture windows can reach soaring sizes, with only structural considerations as limitations. In fact, picture windows can even form an entire wall of glass.
When technology was cruder, glass could only be made in small panes, therefore windows had wooden framework called muntin bars that held the panes together to form larger expanses. Nowadays, there is no need for muntin bars, and contemporary picture windows tend not to use this traditional grid of dividers.
In the late 19th into the 20th century, newer styles of architecture such as Edwardian, Queen Anne, Prairie, Arts and Crafts and Art Deco transformed the functional element of muntin bars into stylish patterns. Today, with brands such as Marvin, adding divided lights to a picture window is a highly customizable feature. Lines need not be straight, and the sky’s the limit.