This strap is called Chairless and is supposedly the most minimal chair possible. Designed by Alejandro Aravena for furniture company Vitra, the Chairless was inspired by an "Ayoreo Indian sitting on the ground with a tight strap around his knees and back." That's all the Chairless is: a strap that you cinch around your back and knees to support you in a sitting position wherever you may feel the need to stop standing or lying down.
Now, I could mention that the most minimal chair in the world is the floor, and we all have one of those already, and I think I will. But in the interests of science, I made my own Chairless from a yoga strap I, erm, found in my apartment. The strap is almost exactly the same as the Chairless, and undoubtedly cheaper (although Vitra is keeping quiet on the price until the June launch).
Is it comfortable? Well, if you define comfort as feeling as if you are tipping backwards while you legs have their blood cut off, then yes, it is one of the most comfortable chairs I have used. Here's a tip from yoga: sit cross legged. If you get used to it, and do it properly, you back will be straight, your legs will remain un-cramped and with full blood-flow and you can stay in the same position for hours. Better, you don't need to buy a branded designer strap to do it.
Chairless [Vitra. Warning: Flash via Fast Company and ]
