The area of each circle decreases as , where is an integer and is an exponent between 1.1 and 1.5, which ensures convergence and interesting pictures. In fact, summing all areas gives the Riemann zeta function, with a starting area for the first circle satisfying the relation

.

For a high number of steps and values of near 1.5, the number of iterations required grows; in that case the number of iterations is limited to one million.

For a variety of designs, extensions to 3D, and estimates of fractal dimensions, visit Paul Bourke's web page.