Ogee arch

An ogee turns its curve halfway: each side rises bowed outward, then bows inward to meet the other in a point. John Henry Parker wrote of the Decorated style, which he dates from 1272 to 1377: “No rule whatever is followed in the form of the arch over windows in this style”, and “the ogee arch is not uncommon”; it “is frequently used in small arcades and in the heads of windows”. With no rule in the record, the construction here is our own, and it is exact. The span is halved by a vesica and each half halved again, so two uprights stand a quarter in from the springing. About the foot of each upright, at a quarter of the span, a quarter circle rises from the springing to the upright; at half the span the same pin cuts the upright higher up, and about that point, at a quarter again, a second quarter circle turns the other way and runs to the middle. The two sides meet upright, half the span above the springing. The hood mould above is swung from the same four pins; only its finial is drawn by eye.