tracery was that of the ogee, which was too weak for structural application and was instead used as a decorative element. The use of the ogee in curvilinear tracery can be seen in the west window of St Mary's parish church in Cottingham, East Riding of Yorkshire. A secondary style, considered related to curvilinear tracery, is called reticulated tracery. Reticulated tracery fills the head of the arch with repeated forms creating the appearance of a net-like pattern. Perpendicular Third Pointed or Perpendicular Gothic developed in England from the later 14th century and is typified by Rectilinear tracery (panel-tracery). The mullions are often joined together by transoms and continue up their straight vertical lines to the top of the window's main arch, some branching off into lesser arches, and creating a series of panel-like lights. Perpendicular strove for verticality and dispensed with the Curvilinear style's sinuous lines in favour of unbroken straight mullions from top to bottom, transected by horizontal transoms and bars. Four-centred arches were used in the 15th and 16th centuries to create windows of increasing size with flatter window-heads, often filling the entire wall of the bay between each buttress. The windows were themselves divided into panels of lights topped by pointed arches struck from four centres. The transoms were often topped by miniature crenellations. The windows at King's College Chapel, Cambridge (1446–1515) represent the heights of Perpendicular tracery. Blind and open tracery As bar tracery opened the way for more complex patterns, masons started applying those same patterns to other surfaces as well as the actual window openings. When used on an otherwise solid walls, such motifs are known as blind tracery, a decorative effect first applied on the west facade of the church of St Nicaise at Reims (1230s). Conversely, tracery was also constructed as openwork screens, which could either match the window tracery behind them (e.g. the Basilica of Saint Urbain, Troyes) or create a visual counterpoint to it, as on the exterior of the west facade of Strasbourg Cathedral. Open tracery in particular was a key feature of the later phases of Rayonnant and Flamboyant Gothic. Arches, windows and tracery Early or Lancet Gothic The simplest shape of a Gothic window is a long opening with a pointed arch known in England as the lancet. Lancet windows may be used singly, as in the nave of Lincoln Cathedral, or grouped, as in the nave