This sofa doubles as a bunk bed

Whether it's a housing boom or bust, square footage is always at a premium in big cities. That's why, whenever possible, we try to find examples of technology used for space-saving engineering, as we did with this a few months back.

But what if you don't want to bring your work home yet remain space-challenged? Never fear: This U.K. furniture site displays a sofa that converts to a bunk bed.

We just hope that no assembly is required.