Wool

None visible. An automated silo and the people who maintain it.

Everyone holds an assigned trade — porter, mechanic, farmer, IT — for life, in a shaft they will never leave. Children are permitted by lottery. The one job nobody volunteers for is cleaning, and it is a death sentence dressed as maintenance.

Allocated labour — A system decides what you will do, and people comply — sometimes willingly.

The clearest illustration of allocation without an allocator you can point to. The system assigns; no one remembers deciding it should.