Rose of twelve
Walk the compass round the rim at its own opening and it closes in six steps. The chords that skip a point cross where each step is halved, so six diameters give twelve spokes. On each spoke stands a circle that touches the rim and both its neighbours. Their centres lie on one circle, 0.794 of the rim, set so that they touch. That circle and the moulding round the rim are the only openings here not found from the figure. The hub touches all twelve, and the six petal rosette returns inside it at the hub’s own opening.
In the faith
At Notre Dame de Paris the north rose, made about 1250, sets Mary enthroned with the Christ Child at its centre, with sixteen prophets in the inner ring of medallions and thirty two kings and judges in the outer.
Sources
- Euclid, Elements IV.15
- Notre Dame de Paris, north transept rose, about 1250
- Friends of Notre Dame de Paris, The Rose Windows