An expandable structure that includes front and rear structural units having inside-facing surfaces parallel to one another, a retractable top that spans the front and rear structural units, and first and second retractable partitions each of which spans and connects the front and rear structural units. The front structural unit is fixably attached to a substrate and the rear structural unit is mounted on a rolling mechanism so that the rear structural unit may be moved away from the front structural unit in an orientation perpendicular to the face of the first structural unit to a distance equivalent to a deployed depth of the first retractable partition, the second retractable partition and the retractable top.