Struycken's computer drawings from the 1970s always depict lines, while the early ones were exclusively in black-and-white. Around 1980 he changed this practice and began making with individual dots in colour. He also used a plotter linked to the computer - a drawing device in which various coloured felt-tip pens had to be placed.
Briefly, the SHFT program is based on wave interferences in two-dimensional space that in theory can continue indefinitely. What is striking about the program's resulting drawings are the recurring almond shapes and elongated circles that also occur in moiré patterns.