The Blit terminal (circa 1982) was an early (possibly the first) remote windowing system by which multiple UNIX processes could operate on the same screen. Originating from Bell Labs, it’s considered a major influence on MIT’s X Window System which still in use on many systems today.
Xerox Star user interface from 1982. The Lisa and Mac interfaces that would follow a couple years later are dismissed by some today as being merely a direct ripoff of Xerox’s work…but in watching this it becomes apparent that Apple’s UI was in fact an evolution of these concepts, not a 1:1 copy. The Star UI has little to no direct manipulation, nor any visual distinction for radio buttons or check boxes. In other places, such as networking and printing, the Star was many years ahead. The Star UI laid the foundation but it was not copied whole cloth as some will claim.
Xerox Mockingbird (1980)