It has an interesting GUI. Text is live (as in everything can be a menu), and selections can become objects of commands.
It is commonly said that Plan 9 from Bell Labs is more UNIX than UNIX. This idea of sliding the view along an infinite plane, in turn, seems to me even more UNIX than anything I've seen or heard of. Not having used -- and in fact only having heard of in passing -- Oberon before, I can't comment on how Unixy the remainder of the system is, but none-the-less, this right here seems to capture the essense of UNIX. In all the times I have been impressed by well composed presentations, never have I questioned the need for "tricks" like screenshots and videos to get a coherrent presentation of interactive tasks or information from software external to whatever tool was being used to run the presentation.
I imagine that you could get lost quite easily in an infinite plane, so you'd need to be able to zoom out to find your windows but if you have too many windows opened then you have to zoom out so much than it's becoming hard to see which windows is what..
Workspaces seems a better way to organize your windows (even though it can also be difficult to find the workspace which contain the window you want).
At 1:1, imagine a regular view.
Below some threshold effective resolution, imagine condensed information. Instead of miniature, unreadable windows, one might display a simplified view, say a Metro-style color coded box with -- relative to box size -- a big icon and document title.
Below yet another threshold, condense more, using conventional icons instead of Metro.
At lowest zoom level, display a one-dimensional list of everything. Searchable of course.