This one serves two drinks https://news.ycombinator.com/item?id=42809268 https://news.ycombinator.com/item?id=42809268 Sort of like https://en.wikipedia.org/

This one serves two drinks https://news.ycombinator.com/item?id=42809268 https://news.ycombinator.com/item?id=42809268 Sort of like https://en.wikipedia.org/wiki/Inexhaustible_bottle https://en.wikipedia.org/wiki/Inexhaustible_bottle