Sören@nevali incidentally, this mockup looks like a blend of Macintosh System 7 and BeOS (which didn’t exist yet)
Mac menu bar, including Chicago typeface
BeOS-style isometric icons and “tabbed” title bars
Uli Kusterer (Not a kitteh)@chucker @nevali This does look very BeOS! <3
That said, they already had tab-style titlebars early on during Lisa/Macintosh development and then discarded them again. https://www.folklore.org/StoryView.py?project=Macintosh&story=Busy_Being_Born.txt&sortOrder=Sort+by+Date]