The REK bookcase, designed by Rotterdam-based architect Reinier de Jong, is ingenious both in its simplicity and functionality. Made in five parts, the zigzag-stacked components slide in and out of each other – expanding to accommodate more books or to fill a longer length of wall, if desired. Compressing the shelves together allows the bookcase to fit into a smaller space or avoid a half-empty look if there are only a few books to display. The zigzag construction automatically creates sections of different height — big ones to fit tall books, artwork or sound systems, horizontal slots for magazines or a DVD player. The owner can play with the design to customize a look or add more bookcases to create a larger library or architectural pattern. Finished with a high-gloss white laminate on the outside and a warm gray stain laminate on the inside, the REK adapts to most any décor. The more we studied it, the more we admired its smart, flexible design.