THE Flex chair it is Madhu RajanThe thesis project, presented at ICFF 2025 in New York, a side chair made from a single shell of fiberglass-reinforced nylon. It has no joints, no foam, no upholstery and no additional structure beyond the four legs. The chair’s ability to bend and yield to body movement is entirely a product of how it is shaped and where it is thinned.
It’s complicated to make a chair that properly fits the human body, and the history of seating is essentially a history of solutions to this problem: mechanisms, springs, cushioning, each of which adds weight, complexity, cost. Madhu Rajan approached the problem from the opposite direction, going back to the eternal beginning”less is more.”
Flex Chair © Madhu Rajan
Flex Chair © Madhu Rajan
Original © Madhu Rajan
Flex Chair © Madhu Rajan
Components of the Flex chair © Madhu Rajan
Flex Chair © Madhu Rajan
Colourways © Madhu Rajan
Flex Chair © Madhu Rajan
At the sides of the seat, the chair shell features a slit, like a paper cut, that breaks the continuous surface enough to allow the back to move back under load. When you stop applying the load, it returns to its original position. The intelligence of the product lies entirely in the geometry and thickness of the material.
“The concept is based on the efficiency of handling paper, how a single cut or fold can create dynamic movement without additional components. In the same way, the design of the chair introduces flexibility not through additional mechanisms, but through the inherent properties of the material, shaped and refined into a form that naturally responds to the movements of the user.” says Rajan.
This approach has precedents in the history of the cast shell chair, notably from the early 1950s when Charles and Ray Eames pioneered the fiberglass shell chair in collaboration with Zenith Plastics. The pair’s insight was that a single molded surface could distribute body weight over a wide area without the need for padding.
However, their chair did not flex back in response. Verner Panton’s 1960 Cantilever Chair achieved a degree of elasticity through the overall geometry of the chair, with the entire chair acting like a spring rather than a single part. Herman Miller later developed shell chairs with U-shaped notches cut into the transition zone between the seat and the back, a mechanical intervention that allows bending.
Fiberglass-reinforced nylon is an accurate choice for the Flex chair, stiffer than polypropylene but can be made to flex predictably at reduced cross-sections. Unlike most reinforced polymers, which can creep or deform under sustained load, glass fiber reinforcement helps the material return to its natural position. This is like what engineers call “live joint”, where flexibility results from tapering off a section of a continuous structure rather than inserting a separate joint.
Rajan achieved this result through extensive prototype iterations because this kind of work requires physical testing more than computational modeling. The material itself teaches you what it can and cannot do and the form adjusts accordingly. Like electricity furniture purchase is filled with chairs that achieve ergonomic performance through visible and invasive technology, the Flex chair operates on the premise that the best performance is the one that disappears.
