6.3. Parallel tenons. Instead of opposite tenons we can also use parallel tenons. In this way it is possible to create box like slide together structures as you can see in the examples (figure 42 and 43).

7. Coxeter Polyhedra

7.1. Infinite structures. The question arose how to create infinite structures using the kind of pieces developed in the previous section. Staying in the field of polyhedra we can then take the infinite regular polyhedra, found by H.S.M. Coxeter [2] as the basic structures. Both methods, tenons in opposite directions, and parallel tenons can be applied to make slide together structures. It gives the idea of an implosion seeing all the pieces coming together to form the slide together structure.