No need to get fancy creating a design wall. Anything that fabric will stick to works.
Mine is a solid-colour flannel sheet draped over the spare mattress which is leaned up against the wall.
My friend draped an old flannel sheet over some closet doors when she was renting a place.
You do want to be able to apply enough pressure to the wall in order to smooth out a larger piece of fabric that you are sticking to it.