Old icons
Dr. Drang talks about the 1984 original Macintosh Old icons:
In those days, icons were 32×32 pixel images, and every pixel was either black or white. The classic original Mac application icons were the ones for MacWrite and MacPaint.
The original Macintosh screen was 512×342 pixels, so every pixel counted.
The design language of the Macintosh icons in 1984 for application: a square diammond shape (not always followed) and a hand shown doing something, indicating it was an application (application is the name for a program to be run by the user on Macintosh), and how some icons just broke that convention, with sometime good reasons.
I was exclusively a Mac user in the 80s to the mid 90s, and one of the things I loved was the UI was consistent across.