OS X and Windows both have their roots in the 1980s—that's more than 30 years of change, growth, gradual evolution, and in some cases sudden revolution. BetterBuys posted a look back at both operating systems that includes animated GIFs of every major release, from Mac System Software1 to MacOS to OS X 10.11 and Windows 3.0 to Windows 10.
They make for a great trip down memory lane. More interestingly to me, they show both the remarkable refinement and relative lack of change in the paradigm of desktop computing. First, let's look at the Apple operating system image:
The Evolution of Apple's Operating System[s] from BetterBuys
Next, here's the Microsoft image. Note that it starts with Windows 3.0 in 1990. Windows actually got its start with Windows, which was released in 1985. The full post does include information about those pre-1990 releases, though they are absent from the image.
The Evolution of Microsoft's Operating System[s] from BetterBuys
There are also two similar GIFs showing the evolution of OS X's Dock and Windows' Start Menu, as well as animations showing the evolution of Apple's logo and Microsoft's logo. I found the OS GIFs the most interesting, but check out the full post if you want to see the others.