Then I found that $7 bolt of fabric I'd bought a few years ago to make mob hats for our colonial party.
Next, I just laid the poles on top of the fabric and cut out three triangular sections about five feet at the bottom by eight feet tall. I sewed them together on the edges, leaving the front open, and then sewed a sleeve on each seam like on a flag. It's easy to fold up and take down, or to set up and move around. And it's fun to read inside it. My students love it!