Two years ago I vibe coded a recreation of the Mac Desktop Pattern Control Panel to change a website's background.
Demo here: https://jherrm.github.io/classic-mac-desktop-pattern/
Source: https://github.com/jherrm/classic-mac-desktop-pattern
Demo here: https://jherrm.github.io/classic-mac-desktop-pattern/
Source: https://github.com/jherrm/classic-mac-desktop-pattern
edit: holy crap, I just figured it out: "Set Utilities Pattern" replaces the background pattern of every desk accessory, such as the Calculator and Scrapbook apps, Find File, Key Caps, Puzzle— with the pattern you chose. What a different time that was!