Ed is a visual line editor, and if that's a GUI then we can stop talking about PARC and just agree that Brainfuck is as good as Python via Turing Completeness while we're at it.
If it's the turtles all the way down, any blinking light becomes a GUI, for what is a pixel?
If it's the turtles all the way down, any blinking light becomes a GUI, for what is a pixel?