Well it is kinda cheating but Linux does “run” on a intel 4004 running a MIPS emulator

I think you could cook something like a 4-bit turing complete computer with around 100 transistors or so. And i guess turing completeness basically means “it will run with enough elbow grease” in this case

(if we exclude memory from the transistor count…)

it is the workspace indicator of gnome

There are 8 workspaces open (lots of windows) and the second one is currently on display