here are some samples i have been doing using foam to create a puffy texture, and also trying to make my own inflatable square...

 My first attempt i used PVC and a hot iron to glue the sides down. It worked well so i tried a bigger size...

 On my second attempt i tried a bigger square and also sewed it to calico to see how it would look. I had a few holes in the the fabric and after a few fixes with the iron it stayed inflated. 

 Trying it out on the stand to see how it would look...