Birgitte Borup and Carsten Nikolaj Becker designed the Puzzle table and chair set in 1997 for the Danish library outfitter BCI. The simple, curved birch ply design allows for multiple tables to be pushed together, and the stools nest in each other to make wheels, enabling kids to turn any library corner into a re-enactment of the siege at Helm's Deep.
Puzzle is apparently still in production, and even though BCI says it was "designed with a variety of uses in mind, including private use," it's only sold through Eurobib, BCI's library design distributor, where "private users" usually don't go.
Puzzle, by Birgitte Borup and Carsten Nikolaj Becker [bci.dk]
Puzzle, with a table and four stools, is EUR544 before VAT at Eurobib's Ireland web shop [eurobib.com]