I have actually seen the Atari Transputer machine at a show in Paris.
If memory serves, one of the demos they had was the mandelbrot drawing
program with the 4 transputers each taking a part of the screen and
computing it at the same time while a stock ST had the 68K calculate
the entire screen by itself.
IMHO, Atari had a lot of great products in those days. Unfortunately,
most of them were never really marketed or even so, were marketed
poorly.
Ben