It was only when I later re-read the comment I replied to, with the part about Bill Atkinson not knowing about the border-radius feature in CSS, that I realized what was going on.
At least I hope my note about the pixelated icons may have been of interest to a few.
It was because she had only two colors to work with, black and white, and only two icon sizes, 16x16 and 32x32.
Steve Jobs and Bill Atkinson only got 32x32 B&W icons for their own portraits:
https://www.folklore.org/Steve,_Icon.html
> Icons were only 32 by 32 black or white pixels, 1024 dots in total
Susan posted more examples here:
https://www.behance.net/gallery/81132387/Macintosh-icons