150px|thumb|right|Architectural trefoil
150px|thumb|right|Architectural trefoil
A trefoil () is a graphic form composed of the outline of three overlapping rings, used in architecture, Pagan and Christian symbolism, among other areas. The term is also applied to other symbols with a threefold shape. A similar shape with four rings is called a quatrefoil.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).