Based on user Ramin's very pleasing design, but the jagged looping has been corrected to loop smoothly, all the circles are now perfectly round (one circle had a flat edge in Ramin's original design), and a little bit more margin has been allowed so the animation doesn't go quite as close to the edge of the frame.
View Ramin's original animation here https://lottiefiles.com/101779-circle-background-animate