I can't remember what they are called. I use them on my carpet. The carpet in my house is the cheap stuff until Home Depot gets in here and tiles. I think they are really prolonging the life of my knees. I got my puzzle mats (that's probably what they are called) at Target. 4 in a pack for 15.00, the solid black ones, not the colored ones. A fellow poster posted in the past that the colored ones stick to you. If I could rebuy them, I would get the ones that Pinky has. They look cool. I still live for the day when I can build a platform similar to the ones they use in the classic Firms. I know how, I just haven't done it.
I have puzzle mats and they are on carpet (berber). I also got mine at Target and have had them for a couple of years. They are very durable and work great!