C program for rational approximation of real numbers. Two approximations are returned, one on each side of the input. The method is to truncate the continued fraction representation of the input, and then slightly modify the last term of the truncated representation. For instance, the norm of the Eisenstein integers produces a similar pattern of concentric circles in a triangular grid. See also Eric Weisstein's entry on the Circles and Squares Fractal .
Source code is available for producing similar figures.
Ian Connel's Elliptic Curve Handbook Continued fractions . Curious continued fraction evaluations from MathSoft. My favorite proof that there are infinitely many prime numbers Golomb Ruler Calculations . Keith Numbers . Keith Matthews' Number Theory Web Recreational topics from the theory of numbers David Eppstein , Dept.