These surprising elements are one of Gaudí´smaximun expressions as a creator of forms.Of larger size than other elements on the terrace, each one of the six stairwells contains a water deposit in the upper section and connects with the attic by means of a winding staircase.Moreover they have a series of hollows that help to renew the air in the attic.Gaudí designed four different models of conical form that, covered with "trencadís", correspond with the four exits lined up with the exterior façades. Of the six models, two are quite similar and another two are repeated in ochre stuccowork by the stairwells that are situated near the rear façade.