In the conceptual design phase for a new structure it will often be fruitful to make ex-periments with different structures and loads to see the stress trajectories and the “flow of forces”. Now the question is whether these graphical pictures gives more than just a qualitative idea of “the force paths”, that is - a rough guideline for where to place the material (Thamm 1999)? The postulate of this article is that the stress trajectories can be used to identify the geometry of the minimum weight structure, the so called Michell structure, for the specific geometry and load.