[math-fun] One base, two digit sets

Knuth has proposed two positional base + digits schemes for representing complex numbers. Base i-1, digits {0,1}: https://en.wikipedia.org/wiki/Complex-base_system#/media/File:ComplexTwindra... , gosper.org/basei-1.png and Base 2i, digits {0,1,2,3}: https://en.wikipedia.org/wiki/Quater-imaginary_base These systems are closely related, because (i-1)² = -2i . So in base 2i, you can get the mirror image of the twindragon system by using the digits {0, 1, - i - 1, -i} instead of {0,1,2,3}! —rwg