Furniture dimensions don't come out of the air. They come out of heavy research that, thankfully, a lot of people have already done for us and written books on; if you're a designer, you ought have a copy of one of these books (see bottom of this entry). While these
Sit on this chair you won't fall, design by Norwegian Designer Peter Opsvik in 1983, named Gravity balans. "It is not a chair, it is a way of life." Traditionally, people surround themselves with one kind of furniture for resting and another kind for performing activities. Why couldn't we alternate between these body postures on a single chair?