"The Triskele symbol, otherwise known as the Triskelion, is a trilateral symbol consisting of three interlocked spirals. Widely regarded as one of the oldest Irish symbols in existence, it appears on the Newgrange kerbstones, which date from approximately 3200 BC. Triskeles feature prominently in both ancient and modern Celtic art, as they evoke the Celtic interpretation of the three realms of material existence: earth, water, and sky (and all their interconnections). The symbol is also thought to represent the three worlds: spiritual, physical, and celestial." - ancient-symbol.com