Page "Trullo" Paragraph 18

Additionally, the cone itself may have a symbol painted on it ( as shown in the picture of the trulli in Alberobello.

) Such symbols may include Christian symbols such as a simple cross, a cross on a heart pierced by an arrow ( representing Santa Maria Addolorata, i. e. Our Lady of Sorrows ), a circle divided into four quarters with the letters S, C, S, D in them ( for Sanctus Christus and Sanctus Dominus according to one source, but more likely the initials of Santo Cosma and Santo Damiano, the two saints the local basilica is dedicated to ) and quite a few others.