Made with fabric samples given to me on Freecycle. The type you get when you buy some curtains. I am NOT much good at sewing, so I would not advise anyone to consider me an expert about how to do this, however it might give you an idea worth considering. I simply made it up as I went along.
I took some corduroy and cut to the required size.
I then used fusible webbing to attach the bits of material in a random pattern over the top.
I spray basted the completed piece to some wadding and a backing material.
Then I random quilted it ( awefully badly ) to provide a more robust mat, then edged it with binding ( to the best of my limited ability)
As it was going on the floor I Scotchguarded it to at least keep it moderately clean. I didn’t use washable materials specifically for the top but I did handwash them to see if they would take a wash. You may want to use machine washable material.
The layers of material made it tough on the machine, it managed but be careful with your choice of needle and choose something for a thick fabric.