Suggestions:
· Cut up lino has many uses
· Cork tiles from Bunnings work well
· Wood boards and nail rats by the paws. Wrap wooden boards in cling film first so they stay relatively clean. Ensure nails are correct length so they don’t go through to the other side. Recommend boards to be min.1cm thick.
· Wood or Plastic bread boards with a hole drilled in each corner. Thread string through each hole and tie to a leg.
· I have used in the past the kids connecting EVA foam connecting tiles. Each matt is 60X60cm for $10 and I cut them into four 30x30cm mats, they are about12mm thick. I use blue, and they can be cleaned and reused many times.
https://www.clarkrubber.com.au/products/17654p-eva-play-tile-solid#variant=TGlnaHQrQmx1ZQ==