I found this image on Pinterest
but could not find who to recognise/praise for it (my apologies to the clever inventor). I have been going to make one of these
(see: http://www.theultralighthiker.com/tarp-bathtub-groundsheet/) out of Tyvek (will be soon for my new tent). I think it will be a simple matter to add some ‘pockets’ as illustrated in the first picture so that a one person groundsheet can do double duty as an ultralight chair with the addition of a couple of hiking poles (as shown) or a couple of broken off sticks. Maybe a couple of webbing straps need to be added. I will experiment. As I have said before: ‘Watch this space…’
I don’t know whether it will replace my Big Agnes Cyclone chair which has done much great service (but no doubt cold be made lighter by omitting the carbon fibre poles within it and substituting sticks found ‘up the bush’ instead: http://www.theultralighthiker.com/cyclone-chair/
My thanks also to Jenny for contributing her interesting ‘bush chair’: http://www.theultralighthiker.com/the-ultralight-bush-chair/
PS: My thanks to Ron Mehringer for this information: ‘The ultralight chair/groundsheet was invented by Jerry from Hammock Forums and is called a Jerry Chair.
Thanks also to Dave Sailer for drawing my attention to this intersting modification of the jerry Chair making it into both chair and pack cover: http://www.hammockforums.net/forum/showthread.php/138529-Jerry-Chair-Pack-Cover-Ground-Sheet?p=1790368#post1790368
This is certainly how great ideas evolve.
Another DIY idea: https://ripstopbytheroll.com/pages/customer-project-trekking-pole-chair