My sister-in-law asked me to convert a t-shirt, that she had had for some time, into a cushion cover. It was not a difficult task and was finished very quickly. I had planned to put piping around the cushion but because of the flexible nature of the t-shirt fabric I found that would have been too tricky so I left the cushion plain, with a zip opening.
front view
back view
Gippsland Granny 
Really cute Heather!
Thanks Kate.
That’s adorable!
What fun!