Imagine a robot programmed to shuffle balls from a bin and pick one, like for the lottery. The implementation is deterministic, but the outcome 'random'.
Edit: (about LLMs) balls on the bin repeat if we like them more, and instead of numbers we put "tokens" on them: pieces of text. Also, the bin gets updated every time you take a ball out. The human can then interpret the text from the balls to form a meaningful message. A significant improvement from geomancy (\s?)
"and there is nothing new under the sun"