Nicely done Jerry. That symbol means the 4 elements AIR, WATER, FIRE, EARTH and that they are all part of the whole. The symbol as cut very closely resembles the Celtic version of that.
Celtic Shield Knot, Germanic, Protection, Amulet,
The shield knot is an universal ancient symbol and has been used by a variety of cultures for protection. The Celts put this design on warriors shields and on clothing, to ward off evil & sickness.
DW