I was looking through lucepedia.com (great design website) and I came across this wall art/chair designed by Dror Benshetrit.
The idea of this "chair" is that you can keep it hanging on the wall as wall art and then when you are in need of extra seating you can pull it off the wall and use it as a chair
This object has a metal hinged structure with a wood veneer cover which enables it to hang flat against the wall and then fold out into a chair. And because this chair has a wood surface you can design and engrave the art yourself.
I thought this was a great idea especially for condo or small space living where you don't have room to store extra seating.