Reversibly assembled cellular composite materials (RCCM) are three-dimensional lattices of modular structures that can be partially disassembled to enable repairs or other modifications. Each cell incorporates  structural material and a reversible interlock, allowing lattices of arbitrary size and shape. RCCM display three-dimensional symmetry derived from the geometry as linked.
The discrete construction of reversibly assembled cellular composites introduces a new degree of freedom that determines global functional properties from the local placement of heterogeneous components. Because the individual parts are literally finite elements, a hierarchical decomposition describes the part types and their combination in a structure.
RCCM can be viewed as a "digital" material in which discrete parts link with a discrete set of relative positions and orientations. An assembler can place them using only local information. Placement errors can be detected and corrected by assembly reversal. These materials combine the size and strength of composites with the low density of cellular materials and the convenience of additive manufacturing.