As early as the late 1920s and early 1930s, roughly at the same time as the development of the 'chaise longue' by Le Cobusier, Perriand and Jeanneret, Hans Luckhardt developed so-called movement chairs (partly together with Anton Lorenz). He dealt with the medical problems of sitting and, based on this, developed test models at the Thonet company, which ultimately led to the production of a series of 'Siesta Medizinal' deck chairs. The special and completely new thing about it was the mechanism, which enabled the synchronous adjustment of the support surfaces for the back, thighs and lower legs by means of a 'link gear' by simply shifting weight. This lounger is located in the Vitra Design Museum, Weil am Rhein and many other international museums and collections.