The maze is create by repeatedly choosing a starting position and colour at random, then reversing direction, again at random, avoiding any obstacles. Software written by the author as a school-child on an Electron computer.
Great detail can be seen in this image which consists of only 320 by 250 pixels. Many pictures shown here are made up of over one million pixels. The printer can only actually reproduce eight colours, from the superimposition of three primaries. The other two hundred and fifty shown here were created by dithering those eight.