This lecture focuses on variable height trusses, exploring the influence of changing height on the forces in the members and diagonals. Different typologies of variable height trusses are investigated, starting from the parabolic shape of the arch-and-cable and considering symmetrical variations. The equilibrium of a lenticular truss model with applied loads is analyzed step by step, showcasing the resolution of forces at each node. The lecture emphasizes the symmetry in force distribution due to symmetric loads, highlighting the constant compression in upper members and the nearly constant tension in lower members. Examples of historical and modern lenticular trusses are presented, demonstrating the benefits of parabolic truss shapes in maintaining constant forces.