Defying the law of gravity, making the structure disappear or the building stand with no visible supports, has been a source of inspiration and unfulfilled desire for engineers and architects, who, realizing that the laws of nature are invincible, have attempted to create an illusion: to make it look as if these laws were not respected. Gothic flying buttresses, catenaries and braces barely visible from a certain distance, the arches built with small stone voussoirs spanning tens of meters, or the vaults and domes are all well-known forerunners of these perceptive challenges...