Starting from the generic image of the gargoyle, the aim is to observe the movements of circulation and water conveyance. From the gutter to the gutter, these observations will allow us to think of forms induced by these logics of flow. The back of the gargoyles of the cathedral of Strasbourg lets see the expressiveness of the stone backs, tense or curved. Their inverted necks become the hollow receptacles of rainwater whose circulation softens the rigidity of the forms. The workshop proposes to leave the imagery of the bestiary by keeping the notion of fluidity, rigidity and inflection of the forms allowing to guide, slow down or accelerate the flow of the water. The rainwater that carries garbage and dead leaves produces erosion, generates a form that pukes or filters, a form that can expand to become a canopy or draw the contours of a square. The pieces thus created will become gargoyles of uses solving real technical problems.