OS X, now called macOS, was based on the NeXTSTEP operating system. And one innovation of this operating system was large full-color icons.
With the introduction of new icons this year with Office 365 (including the 2019 retail version), I felt the need to create this:
In 2001, Office v. X was released. It’s design was very distinct from Windows, and also very aqua-y. The maximum size was 256×256 pixels. The 2004 icons I found were oddly sized 128×128 pixels. The resolution of the 2008 and 2011 icons went up to 512×512 pixels. These were also the last OS X-specific icons for Office.
Starting with the 2016 version, the icons design of the Windows version was also used with macOS. And because of higher resolutions of displays, the dpi-count of the icons went up from 72dpi to 144dpi, making the 2016 and 2019 icons sized 1024×1024 pixels.