Everything in balance. The colors represent the cardinal directions and the elements. A wine wraps around the compass with a Yin and Yang symbol in the middle to remind us that in the march of time everything must be kept in balance.
I have been doing stained glass or mosaic art works for 10 years now. In college I got a special scholarship to continue honing my skills in this particular style. These artworks take a long time to do and to complete.