One Sheep Sweater
"One Sheep Sweater" (2010) by Christien Meindertsma is exactly that.
From the website:
We are currently working on a new collection of knitted sweaters that are each made from the wool of one of these merino sheep. There is only one flock of merino sheep in the Netherlands, owned by Mathee Kamp. The sheep have been shorn and the wool is on the way to be washed and spun.
http://www.christienmeindertsma.com/index.php?/projects/one-sheep-sweater-2010/




