 In November 1958, Klein exhibited again in the Iris Clert Gallery with Jean Tinguely, with whom he had developed a friendship with during his "Monochrome Propositions" exhibition.This friendship evolved into artistic collaboration sometime during "The Void".The joint exhibition was titled "Vitesse pure et Stabilité monochrome" ("Pure Speed and Monochrome Stability"), and consisted of the monochrome aesthetics of Klein combined with the mechanical, dynamic, and often interactive nature of Tinguely's art.