obviously this guy ties flies for fly fishing. The tool he uses for the thread is simular to a Rites Bobbin. I fly fish but dont tie flies. So if anyone else know exactly what he uses for the string Id be interested. I think he should of used a thicker string to drag the toy but it looks like a fun project.
The house thing seems more like it is for people, not for a cat. There is a reason that cat trees are shaped and designed the way they are. A cat can pretty much sleep anywhere, though height is very much appreciated by many. However, a cat tree often provides an outlet for scratching and climbing. While not as pretty, I think this doll house concept is much more cat friendly: https://www.youtube.com/watch?v=uYi4H6j8Hts
This is the tallest one of 4 cardboard box cat condos I made for the two new cats I adopted a few weeks ago it gives them access to a very high wall shelf. I bought the boxes and tape from UHaul and then used some white paint I had at home to paint it and then drew on it with a jumbo marker I picked up at the dollar store. The 4 I made ended up costing me about $25 each and range in size from 3 boxes to 8 boxes.
The 5 box tower in the picture is secured to both the wall and floor with velcro tape that I picked up at the dollar store otherwise yes the box structures would slide and tip. Secured they don't move.
I built this one in my basement that didn't need any securing. This is just the plan, I did finish it but didn't paint it since the cats don't care.