The present invention provides modular constructions made of easily assembled and disassembled light-weight materials, where the structural parts of these constructions are made of multiwall sheets that enclose a supporting structure. The supporting structure may be a plurality of bubbles, corrugated or fluted structure that respond anisotropically to pressure applied towards a bendable surface of the two surfaces along a designated line of bending. The second surface opposite the bendable surface is textured allowing printing graphics on it that is not stretched or harmed in the bending area, thereby enabling continuous flow of graphics along the entire printing area. The line of bending may be formed thermally, mechanically or in a combination of thermal and mechanic operations. The sheets are folded upon themselves to form three-dimensional structures. These structures combine together to form modular constructions such as shelf systems, cabinets, closets, vanities and cupboards.