The technical aspects of the windows at Reims clearly fascinated Villard de Honnecourt, who visited the construction site, probably in the 1220s, and made a detailed sketch of the various templates, using a key to show how they fitted into the different parts of the window (the templates are in the lower half of folio 32 recto; the symbols besides the templates match similar ones on the detailed drawing of the Reims elevations on the facing page, folio 31 verso). The early phase of "Middle Pointed" style (late 13th century) is characterized by "Geometrical" tracery - simple bar-tracery forming patterns of foiled arches and circles interspersed with triangular lights. The mullions of "Geometrical" style typically had capitals with curved bars emerging from them. "Intersecting" bar-tracery (c.1300) deployed mullions without capitals which branched off equidistant to the window-head. The window-heads themselves were formed of equal curves forming a pointed arch and the tracery-bars were curved by drawing curves with differing radii from the same centres as the window-heads. The mullions were in consequence branched into Y-shaped designs further ornamented with cusps. The intersecting branches produced an array of lozenge-shaped lights in between numerous lancet arched lights. "Y-tracery" was often employed in two-light windows c.1300. Geometrical tracery is identified by the circular openings at the head of the arch of the window. A common composition is three lights beneath two circles and a third at the point of the arch, such an example can be seen along the aisle at the Lincoln Cathedral in England. Also at the Lincoln Cathedral, the east window is an expanded version of this idea with two interior arches, a total of eight lower lights, four small circular lights topped with two larger circles to fill out the interior arches, and finally above all one large circular shape filled with seven smaller circular lights. Geometrical tracery, in its early stages, had a rule of equilateral law, where the tracery design follows the shape of the arch in an equilateral manner. Additional decorative elements can be implemented, such as foliation or the "spherical triangle". The use of spherical triangles is a later adaption and likely reflects religious significance. "Second Pointed" (14th century) saw "Intersecting" tracery elaborated with ogees, creating a complex reticular (net-like) design known as "Reticulated" tracery.