You know what they call Duct tape? 'The handy man's tool' Guess it really can also be call 'The handy quilter's tool'. :D

Duck tape is a brand of duct tape :lol: :lol:

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.

What is the best way to fasten the fleece or flannel or whatever to the insulation board? I bought lots of off white fleece for this purpose, but haven't bought the boards yet. Doesn't seem like duct tape would stick very well to the fleece.

attach with duct tape. Works like a charm!

This is what I did before I was able to get it attached to the wall and it works fine--just don't let a gust of air grab it and over it goes. Happened a couple of times but I keep my doors open as much as possible, no problem now with it attached.

I would duck tape both sides!!! my mom has done this for murals and she found that if she didn't they didn't hold up as well.