Enter h2o architectes, a young firm led by principals Charlotte Hubert, Jean-Jacques Hubert, and Antoine Santiard. The trio decided the smartest way to approach the problem was to subdivide the older child's room in two, making separate places for both children to sleep and play.

Rather than simply building a partition down the middle of the 140-square-foot bedroom, which would have created two constrained rooms, the architects decided to build up and within. "The idea of putting the bed on a higher level came up quite quickly in order to win space," explains Santiard. "At the same time we decide to incorporate many ways to use the bed/partition (storage, office, climb, hide with interior windows, doors, etc)."

The result is a massive piece of what is essentially furniture, crafted out of several large sections of painted MDF and secured to the ceiling to keep it from toppling. Six-year old Eva plays and sleeps in the upper level, while small cubbies hold her toys, books, and dolls. There's also a built-in desk for schoolwork and drawing. Jean, now almost two years old, mainly scampers around on the bottom level, where easy access to his bed and toys defines his area. The whole structure is painted light blue, keeping it lightly ethereal. And hidden staircases and peepholes abound to create an overall effect is of a fantastical modern playground for two very lucky children.