what type of padding/mats/whatever's do you put on your hardwood floor for LO to play on?

J
I have hardwood floors and want to just let him explore at least in his baby nook to have a little more space than just on his play mat. I've seen those pad tiles used, I've seen just blankets put down, etc. so I was just wondering what the majority use that works. I feel like he slips too much on the play mat to work on crawling or things like that