This Peterson variation began with curiosity about other "Newton-style" approximation processes. A simple one,
One = (x * x) + (y * y); y = (2 - One) * x; x = (2 - One) * y;
produces the fractal called Unity.
One of its interesting features is the "ghost lines." The iteration loop bails out when it reaches the number 1 to within the resolution of a screen pixel. When you zoom a section of the image, the bailout criterion is adjusted, causing some lines to become thinner and others thicker.
Only one line in Unity that forms a perfect circle: the one at a radius of 1 from the origin. This line is actually infinitely thin. Zooming on it reveals only a thinner line, up (down?) to the limit of accuracy for the algorithm. The same thing happens with other lines in the fractal, such as those around |x| = |y| = (1/2)^(1/2) = .7071
Try some other tortuous approximations using the TEST stub and let us know what you come up with!