I took an hour off of my busy schedule on Friday to spend time at an auction preview. It was there that this question came to mind.
Many of you know and understand the question but for those who might not, let me provide some background information.

This is a Roorkee chair available from many vendors. There is also a fair amount of information available for the do-it-yourselfers amongst you.

French curves used in drafting, an early, manual version of CAD (computer aided design.
The product of this imagined unholy coupling is below:

The Hoop Chair – Børge Mogensen (Denmark, 1914-1972)
Description: 1950s, bentwood beech frame, stitched leather back and seat with underside straps, unmarked.
This lot has sold for $1,600.

A side view provides no further answers.

A rear view illustrates some adjustments but no rationale for its existence.
This auction featured more of what many call Modern Furniture or, in New York, Mid-Century Modern.

Søren Georg Jensen (Danish, 1917-1982), Set of Six Teak Dining Chairs and Niels Otto Møller (Denmark, 1920-1982), Model 12 Teak Dining Table
Description: 1960s, Norway, manufactured by Nesjestranda Mobelfabrik, teak crest rail/arms with finger joint, ‘Y’ formed back splay tapers into the turned rear spindle, black naugahyde seats on rounded tapered legs.
This lot has sold for $4,400.
Description: For J.L. Moller Mobelfabrik, Denmark, 1960s, top with banded edge and two pull-out extension leaves, on rounded tapered legs, labeled.
This lot has sold for $2,200.

Charles and Ray Eames, Rosewood Lounge Chair and Ottoman.
Description: Herman Miller, Zeeland, Michigan, models 670 and 671 in black leather with black painted steel and aluminum swivel bases, labeled.
This lot has sold for $3,600.

Herman Miller, Goetz Leather Sofa
Description: Designed by Mark Goetz circa 2000, molded walnut veneer frame with black leather upholstery, loose cushions raised on aluminum legs, unmarked.
This lot has sold for $2,600

Jens Quistgaard (Danish, 1919-2008), Flip-Top Executive Desk for Løvig

Joseph Hoffman (Austrian, 1870-1956), Fledermaus Table and Four Chairs
Description: Early 20th century, beech, including a circular table with eight turned legs, ball finials, circular stretcher, and four arm chairs with flat single piece bent crest rail/arm, triple bent-rail back support, oval bent wood arm supports on eight turned legs with repeating bent wood stretcher, later velvet upholstery.
This lot has sold for $2,000.

Jacques Garcia (French, b.1947), Auguste Lounge Chair
Description: Baker, contemporary, hammered and patinated iron frame with stitched black leather upholstery, labeled.
This lot has sold for $550.
and finally:

Alvar Aalto (Finnish, 1898-1976), Artek Tank Chair and Side Table
Description: Finland, 2003, model 400 chair in bentwood birch with Zebra style upholstery, together with an Artek circular side table, labeled.
This lot has sold for $2,300.
Was Mogensen a fan of dinosaurs? His chair back looks like the head plate of a triceratops.
Somehow, the hoop chair reminds me of one of those cone-shaped devices you see over the heads of blue-haired ladies in hair salons. Most of the other pieces look like they were inspired by the 1960s cartoon “The Jetsons”. The lounge chair would be just the thing to sit in to listen to the hideous aberration, lounge music. The Artek Tank Chair is well-named. Overall, this set of pictures is a good catalog of the horrors of mid-century modern.
I have one of the Eames loungers (copy).
I fall asleep in it all the time.
In Australia, this week Aldi have ‘replica’ Eames chairs and ottomans as part of their weekly specials. Lo, How the Mighty have fallen………
Your detailed analysis of different types of chairs is highly commendable. I have never come across such deep details of chairs ever, it was quite informative and easy to relate to as a buyer. Just wanted to know is it possible to see and experience these chairs in reality somehow. Want to experience them in real.