I made a small scratching pad to try this out, and my cat seems to like it. I think it’s meant to be bigger, but I thought I’d test it first in case I was wasting my time (my cat is incredibly picky and fickle!). I used some cardboard, a glue gun, and some scissors (a ruler might be useful too if you need to cut cardboard strips, as mine were a bit uneven).
You start off by cutting the box/piece of cardboard into strips about 2-3 inches thick. The length doesn’t matter as they’ll be rolled up, but the longer they are the fewer edges you’ll have to worry about sticking together (although they’ll get covered in further layers so it’s not a big deal either).
Then cut out a base that will have your chosen final shape and size (mine was just a small round disc).
Once you’ve got all the strips ready, start rolling one, placing hot glue on the outside as you roll to make sure it stays in place. Carry on doing this and adding additional strips until you get a decent-sized flat round cardboard platform. You can also fold and stick it in a square or triangle instead of a circle, although this is probably the easiest shape to start with. Make it as big as you want and, when you’re happy, let it dry off for a few minutes. Then cover one of the sides with hot glue and stick it to the base you cut out previously. You can also do this as you go along, rolling it whilst resting on the base. Whichever you find easier.
If the base sticks out, trim the edges until it fits the rolled-up cardboard strips.
If you like, you can now decorate the edge and base with a nice wrapping paper (or self-adhesive vinyl). Just cover the side edge and base with it.