Let us return to the first architecture class on structures and the classification of structural efforts. In most structures, whether natural or man-made, compression forces are the primary actors. These are efforts undertaken with equal and opposing loads, applied in the interior of the structure, which tend towards the shortening of the piece in one direction - or compressing it, as the name indicates. It is not difficult to find examples of this: for example, a stone wall or a wooden log can resist the weight of a covering through internal compression efforts that are inherent to each material. Tension efforts, on the other hand, tend to lengthen components in the direction of the applied force of action. Steel, for example, is a material with good tensile strength. It is used in reinforced concrete precisely in the parts where the piece is in traction. But it is also possible for a structure to only have tensile parts, as is the case of membrane, tensioned, or tension structures, which consist of surfaces pulled by the action of cables or ropes in which the masts absorb compression efforts.