Empty product cardboard boxes from Costco make excellent cat condos & hiding places plus they double as scratching posts.
When the boxes finally get nicely shredded, out the go out to the recycler & I go & get some more - all for free of course.
BTW, last week we just added another cat to our herd. He was a rescue cat that was becoming very depressed in the PALs cage at the local Woofy's so we took him home a day before he was due to be fostered out.
That now makes 3 beautiful white cats with one tuxedo for diversity, ha!