How did the English Decorated Gothic style use window tracery?

The English Decorated Gothic style utilized window tracery to transform windows into expansive, highly decorative features that replaced the earlier, slender lancet style.1

Architects employed tracery to divide windows of significant height and width into multiple main subdivisions using mullions. These sections were then further subdivided through intricate stone patterns. The evolution of these designs followed two primary phases:1

• Geometric Patterns: Early tracery relied on combinations of trefoils, quatrefoils, arches, and circles to create netlike designs.1
• Flowing Forms: Later developments incorporated the ogee, or S-shaped curve, which produced fluid, flamelike shapes often referred to as flowing tracery.12

By integrating these elaborate stone frameworks, the Decorated Gothic style prioritized rich visual effects, allowing for larger windows that functioned as complex screens of glass and masonry.1