First start by cutting a piece of felted or cotton fabric. You should make the dementions 4.5 (
For each wall. So make it 13.5")
Next cut your soft fuzzy fabric the same size Then pin all but one of the short sides together.
You are going to want what the good side (The one going to be on the outside.) pinned inside.
Sew around all pinned sides.
Tie off the end.
Cut the uneven edge on the unsewn side.
Turn inside out.
Measure the sides and mark them so you know where your walls will be. I like to put pins in place where the edges are. Just pin the top layer.
Take a firm piece of matte printer canvas and fold it in half evenly.
Now cut the long open end to fit in between the pins.
Now remove the pin closest to the opening and push the canvas in till it reaches the other pin.
Now that you have the canvas in place you can go ahead and remove the other pin. Check the length to the edge of the canvas to be sure it is 4.5.
Now fold the side in half so you have a bend right next to the canvas. Be sure to bend a little canvas in the fold too. Be sure to pin the edge. Even through the canvas. Be sure the side you want facing out is not facing inward in the fold!
Now sew the edge.
The side should look like this now.
Now do the same thing on the other side.
You should have two edges that can stand up on there own. It should look like an open square.
Now cut 10" of elastic. You can see the thickness I bought in the photo. Fold the 10" in half then half again.
Now pinch the two sides together, holding the elastic in place.
Pin the side without the ends facing up. You want to pin both pieces of fabric together and have the elastic in the middle.
Now sew the whole edge.
Attatch clips and your finished!!