Koch curve, a fractal. The image shows the construction of the curve using a Lindenmayer system. The first quarter of the image is the axiom and the second is the constructor. The two remaining parts are the second and the third iteration of the system, (the first iteration makes a copy of the constructor).
All fractals are from self-written tools - linear IFS images from my: "2D IFS Studio", non-linear (rev Julia) from "3D RJIFS", (that also writes 2D rev Julias), escape time Z² fractals from "Julia dream", the rest are from small "hacks".