Elevated deck squats?

For my lower body, I am currently doing elevated deck squats.  In the video, they are using mats to do this.  Unfortunately, I don't have any mats at home.  Does anyone have any recommendations for what to use in lieu of mats?  Thanks.

Of course, you can sit on the first step of the staircase, roll back and put the feet on the second one.

I just wrapped up my series of this using couch cushions.  The ones I have are pretty firm and I just tossed them on the floor for my sets.