For some reason which is foreign to me, the cats do not go near it.  It's like they think it's furniture and they know they're not allowed to scratch the furniture?  I don't know.  Thinking of sprinkling catnip on it.  One thing I noticed when we put it together - the "steps" are too steep for any cat to go up - maybe 95% vertical. Not good.  Will probably play around with that as well.