Bay windows project from the exterior wall with a flat central panel flanked by angled side windows, typically at 30 or 45 degrees. Bow windows follow the same concept with a curved arrangement of equal-width panels. Both styles create an alcove or window seat inside the home and add architectural depth and interest to the exterior elevation. The side panels are typically operable casements or double-hungs to provide ventilation. Available through Marvin Ultimate in wood and Fibrex with a range of interior and exterior finish options.