This is the LC1 Chair, designed by Le Corbusier in 1928.

Here's the Huntsman Chair, designed by Danish furniture designer Børge Mogensen in 1950.

And this is the SZ 02 chair, designed by Dutch furniture designer Martin Visser in 1960.

What the three have in common is leather. Leather of course stretches over time, which 20th-century designers were well aware of. For the sake of product longevity, it was common to design in a re-tightening feature, which all three of these chairs have. The LC1 had laces on the bottom:

The Huntsman, belts on the bottom and back:

And the SZ 02 featured a belt in the back, and laces underneath.

Interestingly, the modern-day version of the LC1 produced by Design Within Reach has replaced the laces with metal springs. Not sure how I feel about that.