When is a chair not a chair? When it’s a ball, or a bubble, a tomato or a pony – or any of the fanciful creations of Finnish designer Eero Aarnio.

Aarnio was born in Helsinki, Finland at some point in 1932 and studied at the city’s Institute of Industrial Arts. Unlike many of his contemporaries, architecture was not the original focus of his studies – he instead specialised in interior and industrial design from the get-go. Following an apprenticeship with Finnish designer Ilmari Tapiovaara and a stint with the Asko Company, he set out on his own in 1962, aiming to live out his mantra that "design means constant renewal, realignment and growth".

While now officially in business, Aarnio’s first major client was himself. He had a new home and was looking for the quintessential “big chair” to provide that all-important focal point. But Aarnio wasn’t after your basic Barcalounger. He set out to create a chair that was not just a place to sit, but an environment unto itself. The result was the Ball Chair, also known as the Globe Chair. This sphere-shaped “room within a room” ensconces the sitter in a sort of cocoon, complete with its own telephone. The sitter can be completely isolated from outside noises and distractions, but can rotate a full 360 degrees on a pedestal to face and join the party, should there be one.

Asko began to manufacture small numbers of the futuristic, fiberglass-covered Ball Chair. They created an instant sensation, putting both Aarnio and his concept of fiberglass furniture on the ever-expanding Modernist map.

Wanting to let more light into the Ball, Aarnio’s next design was a variation created from transparent acrylic. Since there was “no nice way to make a clear pedestal,” the Bubble Chair hangs from the ceiling. A swinging, clear bubble you can sit in – groovy!

From there, Aarnio was unstoppable, winning the American Industrial Award for his candy-shaped Pastil Chair – an indoor-outdoor design that lived a double life as a swimming pool float. More outrageous-yet-functional creations followed, including the sculptural Tomato Chair, the Screw Table (which looks like it sounds) and the Pony, an adult-sized seat that looks like a child’s toy.

Lucky for design fans, Aarnio has continued to push the envelope throughout the decades, bringing his wild creations into the 21st century. His most recent chair, the bird-shaped Tipi, was designed in 2002.

As Aarnio himself once said, "a chair is a chair, is a chair, is a chair ... but a seat does not necessarily have to be a chair”. Thanks to his innovative designs, a chair can be almost anything we can imagine.