The Interlocking Puzzle Loft notches and interlocks various program elements into a tight assembly of volumes to maximize usable space. The existing concrete vaulted ceiling of the 700 sf loft has an undulating elevation of 11'-10" at its low point and 12'-3" at its high point. Not being possible to stack two full-height volumes, each volume is stacked with a half-height element: either a closet or a sleeping platform to provide the full program requirements. All horizontal surfaces are covered with maple wood, and the remaining vertical surfaces are painted white. Natural light bounces off the light shelves over the windows to wash the vaulted ceiling in a soft glow.