Vesica piscis
Two circles of one radius, each set on the centre of the other. Euclid opens the Elements with this pair of circles, though not with the name: either crossing and the two centres give the equilateral triangle of Book I, Proposition 1. Many of the figures below start here.
In the faith
Romanesque and Gothic sculptors set Christ in Majesty inside an almond shaped glory of this outline, the mandorla, as on the west portal of Chartres of about 1145.
Sources
- Euclid, Elements I.1
- Chartres Cathedral, Royal Portal, central tympanum