- Oregon -
Per your plans, I just finished the Staircase. I reversed the plans due to room layout, and decide to add a support -- a 2X2 -- to the bottom step, but other than that the plans were complete and easy-to-follow.
The cat in question took a long time -- like ten minutes -- to discover the utility and great perch at the top. She's virtually in Seventh Heaven as we speak.
What's hanging down is the end of her "mouse". She now jumps from the top perch to my shoulder when I'm working on the computer at the left.