Druid teachers and priests used poetry and pictures (designs) to teach the lessons of spirituality to peoples who seldom had a written language.  This design shows the Celtic view of Creation.  There are four circles.  The circle was a powerful archetypal symbol, and the numeral four had many symbolic meanings; e.g., the major elements of the universe were earth, air, fire , and water.  The bottom circle on the design is a representation of active but undifferentiated energy.  It morphs into a creature, as evidenced by the beak and the eye. It also morphs into a second creature, as evidenced by the beak and eye.  It was understood that the figures were symbolic of all  life's creatures, including mankind.  The top circle contains two creatures, now one, dual but the same.  This was the Celtic view of the duality of mankind and nature: male and female: different, but equal in all matters, and always one.