I just love creating these in the computer and they are so simple to create. Here is the geometry behind creating the symbol.
Start with a large circle. Divide in fourths and place a circle that goes from the middle to the outer edge on the center of the line radiating out. Repeat three more times so that there is a circle in each half along the four lines. Place another circle that is the same size as the others in the middle to mark the area where the smaller circles will be placed along the North and South axis, right where the inner circle meets the lines that divided the large circle.
Then I had a ball playing with the various filters and layer styles. Try it yourself.