After a couple of attempts I found myself with a rounded shape, which refused to lay flat (I guess the tension was too tight). It was better suited as a costume which turned my hubby into a Doctor Who monster!
So I had a good old think about how to rectify the problem, and came back to my main crafty means - knitting! Got some 12mm needles, wound my 'yarn' into balls and here is the result...
Not a conventional rag-rug, it looks a bit crazy, but it is super-soft underfoot and machine washable.
Plus my hubby loves it!