STEP 1
Take an old pillowcase, or in my case an new-to-me-but-old pillowcase, purchased for a very cheap price from a local charity shop. Get a cat (in this case Sili) to inspect it for quality and cleanliness.
STEP 2
See this picture of a pillowcase shopping bag on the internetz.
STEP 3
Find the instructions the red bag lady used to make hers.
STEP 4
As directed, fold in half along the diagonal, pin and cut. Do a better job than I did then have a cat expect your handy work. If you didn’t do a better job than I did, expect the cat to stalk off in disgust (a la Carbon).
STEP 5
Turn the pieces inside out (everything is pretty much done on the wrong side from here on in) then ask the nearest cat (still Carbon) to help fold and pin all the diagonals for hemming. You may think the cat is in the way but you are wrong: they’re making sure you don’t get too over-eager with the folding and that you listen to Martha and fold it in twice, about 5mm a time. Cats are stickler for detail and have claws to make sure you follow their instructions, even when they’re so disgusted with your efforts that they can barely look at you.
STEP 5a
Brief pause for a quick tickle with Carbon because, let’s face it, you’re not going to get any more work done while he’s in this mood.