Called REK, the bookcase consists of five parts, which slide out to accommodate books in the resulting voids as the user accumulates them.

Information from the designer:

The zigzag shaped parts slide in and out of each other, providing as much space as needed. With REK there will be no silly sights of half an empty bookcase anymore because REK will always be full. Also with the different spaces that appear you can arrange your books according to their size.

The outside of REK is finished with white high gloss laminate. The inside is finished with another type of laminate, in this case warm grey satin."