Like many people, when I was a kid I read Edwin Abbot’s wonderful novel Flatland: A Romance of Many Dimensions, written in 1884. Essentially, Abbot posits a universe that has only two dimensions, and then explores what it would be like to live in such a world.
I imagine that when people in Flatland eventually developed computers, their user interfaces would be one dimensional, since in 2D you can only see things along a line. But eventually somebody would start thinking about the crazy notion of providing fully 2D computer interfaces, in the spirit of our own recent ideas of immersive virtual reality.
When that happens, I wonder whether there would be pushback. Maybe people would think that going full 2D is just too crazy, and they would end up settling on something more practical, like 1.5D — perhaps lines with layers of depth.