  In this paper, we present an algorithmic approach to design and construct
planar truss structures based on symmetric lattices using modular elements. The
method of assembly is similar to Leonardo grids as they both rely on the
property of interlocking. In theory, our modular elements can be assembled by
the same type of binary operations. Our modular elements embody the principle
of geometric interlocking, a principle recently introduced in literature that
allows for pieces of an assembly to be interlocked in a way that they can
neither be assembled nor disassembled unless the pieces are subjected to
deformation or breakage. We demonstrate that breaking the pieces can indeed
facilitate the effective assembly of these pieces through the use of a simple
key-in-hole concept. As a result, these modular elements can be assembled
together to form an interlocking structure, in which the locking pieces apply
the force necessary to hold the entire assembly together.
