An ideal structural material should be light, strong and tough. Surprisingly, very few materials offer such a combination of properties. Among lightweight materials (with a density inferior to that of water), woods have the best combination of strength and toughness. This project aims to create new lightweight materials capable of outperforming woods. We believe this can be achieved by designing lattice materials: these are interconnected arrays of struts, like honeycombs for example. The main advantage of lattice materials is that their topology can be designed to obtained specific combinations of properties. In this project, we will use 3d printing to produce lattice materials designed in such a way that it will be difficult for cracks to propagate inside them - this is key to achieve a high toughness. Finally, we expect these novel lattices to be tougher, stronger and lighter than conventional existing materials such as wood.