The hay rack was just a grid that was bent into a semicircular shape then I added zip ties very loosely to each corner then hung it up with S hooks. The tunnel is another grid bent in half circle shape and I used small binder clips and attached fleece to it.
This is a cage I had a couple of years ago. It was my favorite of all my cage designs and when I get the space again, I want to build another cage like this one.