A class of zipper fractal functions is more versatile than corresponding classes of traditional and fractal interpolants due to a binary vector called a signature. A zipper fractal function constructed through a zipper iterated function system (IFS) allows one to use negative and positive horizontal scalings. In contrast. a fractal function constructed with an IFS uses positive horizo... https://www.roneverhart.com/AMS-Neve-1073SPX-Single-Preamp-and-EQ-p33827/