This family of stools by German designer Ellen Heilmann can be used as tables or seats.
The Royal Family comprises three American nutwood bases of different heights and three dark green cotton cushions. Each element is interchangeable and can be paired up or used as a single piece of furniture.
Here's some more information from Ellen Heilmann:
The Royal Family consists of three stools which build a modular system. All parts of every stool can be used separately for sitting or as a table. Jointed The Royal Family builds an uniform stool-group, in which everyone is on the one hand visually similar and on the other hand each is individual, like family members usually are.
Material: american nutwood, dark green cotton.
Dimension: 310 mm x 470 mm