Construction Design Mathematics: how to draw a large Geometric window in the Gothic style

How to draw a large Geometric window in the Decorated style

School curriculum: Key Stage 4 Mathematics: Drawing the Altrincham window would support the teaching of the 2D stacking of circles. It is concerned with the optimal arrangement of placing four congruent circles within a circle, and related problem solving using Pythagoras.

Altrincham Baptist Church, Cheshire was constructed towards the end of the Gothic Revival movement in 1904; its west window is shown on the accompanying pages. The window comprises five lancet lights. From the left, there are two lights under a circle within a sub-arcuation; then a single light under a circle circumscribing four congruent circles; then two lights under a circle within a sub-arcuation; all within a larger arch.