Time for our annual check-in with Reinier de Jong (see complete list below). The Rotterdam-based designer's REK expandable bookcase design is amazing enough that since its 2008 launch, it's experienced multiple popularity booms on the interwebs. The only downside to the REK is that you need a good amount of free space to put it in; de Jong's latest, the MODULAR shelves, can also take up a lot of space, but give the user the option of building them up over time.
The MODULAR's building block is a single and simple rectangular unit, fitted with holes on two axes for dowels.
More Reinier de Jong projects from over the years:
2008: REK expandable bookcase
2009: KOPS chair
2010: VOLT table
2011: DEX desk
2012: REK coffee table
2013: STEEL folding chair