It is a slight modification of a program published on pouet in 2021. It just adds several new minor features to this program: perfect dithering, timings, the 10/11 autotoggle, keyboard handling, ... It uses 4 colors and textures to simulate 8 colors. Generated pictures are 256x256 raster images which may be treated as 512x256 b/w images. It is very likely that this algoritm implementation is the fastest known Mandelbrot set computation routine for any PDP-11 system.
The bin-file is here.
Sources are available on github.