I put this together for Benji and Cricket to play on. It fits on top of Benji's cage. Made it out of 3/8" dowels and 1/2" PVC.
The three top pieces can be turned to where ever.
Double AWWW! Looks like they like it! If it were me, I'd be putting something underneath it though...newspaper at least. I can't stand it when Ollie sits on top of her cage and poops down into it. Seems like it ends up in her food bowl every time. Thankfully she rarely picks the cage top over her other gyms.
Edited to say: I really like the rope wrapped around it. I bet they have fun climbing up and down.