Google enters the spirit every year and on Sunday it dedicated an animated Doodle to Celtic Triskele, an ancient symbol of Irish culture. Triskelion, derived from the Greek word triskeles, means "three bones", going back to the Neolithic era but not gaining popularity with Celtic culture until about 500 BC.
The Triskelion – also known as Triple Spiral – has three interconnecting coils positioned to appear in constant motion, moving outward from the center. Triskelion's three spirals often seem to reflect cycles, advances and revolution.
The ancient symbol is open to a variety of interpretations but is usually associated with a trinity of themes. For some, it represents life, death and rebirth. past, present and future; and spirit, mind and body, just to name a few.
Still others unite the spirals with the Holy Trinity – the Christian doctrine that describes God's makeup as father, son, and Holy Ghost.
One of the most common interpretations that Google chose to focus on is that the spirals represent the three worlds of the material world – the earth, the water, and the sky.
Anyway your interpretation is happy St. Patrick's Day!