I threw this small quilt sandwich on my frame and went to town.
Repeating Circles in a circular pattern is how I make this design.
I used a longarm 4 inch circle ruler (below).
When I move the circle around I use the red tape to mark the distance that I move my ruler.
Start by quilting a circle then slowly move your circle ruler counterclockwise. Match up your stitch line with the edge of your mark (tape line) on your ruler. Go completely around your circle and repeat the process all over again until you have completed your Spiro-Quilting Circle.
Once you get to the last circle, make sure that it is centered between your first and your previous quilted circle. This will help to even out your design. This method is not mathematically made, it is creatively made. If you have quilted with rulers you know that even being off by 1/8 of an inch is very easy and if you try to mathematically make this design work you might end up pulling out your hair. I have done this process the creative way many times and it has worked for me. So, have fun with it and try different ways that will work for you.
I hope this diagram is helpful.
Spiro-Quilting can only be done with patience so slow down and have fun.
Take a break and give yourself a playtime.
You never know what your creative side will come up with.