This picture has been made by writing original C++ code on a computer, where the colours were chosen with the same creativity and freedom that an artist uses when confronted with a blank canvas. It is a fractal, the Julia set of a rational function.
Much larger canvas or paper prints can be created if required, with no loss of quality.
For more information:
https://gcboore.com/pages/cd10-julia.html
https://gcboore.com/