The Propellor Stool is attributed to Kaare Klint, the legendary Danish architect and designer. It is said that he designed it in 1930.

The folding stool is named for the legs, each of which are one half of a cylinder. Fold it shut and you can see the magic of the craftsmanship.

Here's the thing: Klint never actually got to sit on the Propellor Stool, not even a prototype of it. The design "was initially thought to be too complex to put into production," writes Carl Hansen & Son. "The 1930 design quickly attracted attention, however, and was featured as a concept in several design books."

Klint died in 1954, the stool having never been realized. A prototype was finally made in 1956 for a Klint memorial at the Danish Museum of Art and Design. It finally went into production in 1962.

Also, the design credit for the stool gets a little muddy:

Remodelista writes that "The Propeller Stool came into being in 1930 as a school exercise by one of Kaare Klint's students."

The Morentz gallery, which counts design historians among their staff, states that "In 1930, a sketch [of the Propellor Stool] was created as a school project by a student of Klint at the [Royal Danish] Academy."

Neither names the student. According to the Danish Design Store, in 1930 Klint did collaborate with student Edvard Kindt-Larsen on the design of a furniture piece; but that was the Mix Chair, which went into production immediately. Aesthetically, the Mix Chair has nothing in common with the Propellor Stool, as you can see:

Only 300 Propellor Stools were made in that 1962 production run, making originals extremely rare. However, today you can buy a new one, as Carl Hansen & Son has put the design back into production.