The RHEL 7 book from OP is most certainly still relevant. For example, my department at work has not managed to switch over to the brand new RHEL 8 machines just yet.

The puzzling part is fun, because you are constantly learning new ways to use your body. See how to balance, how to move around, etc. I have found that dancing gives a similar learning challenge. Especially the more free-form dances like salsa and bachata. It’s fun learning new moves every week during the lesson, and then try to see if you can put them to practise during a party.

And don’t worry about beeing to stiff. If you can balance around boulders, you can get your body to move around for dancing too. Just takes some practise. I currently do both, and feel like I lack dexterity more for the climbing than for the dancing.

And unlike most of the hand-friendly options mentioned already, you do have to use your hands and arms a lot. Just not in a way that puts any stress on them.

Point 1 has to be chosen when the cat is young. Forcing an outside cat to suddenly only be inside often doesn’t work.

I adopted a 7-year-old cat from the shelter, and after a week of having to be inside all the time, he got more and more frustrated. After a week and a half, he escaped during the night. In the morning, while I was panicking, he came strolling in as if nothing was wrong.

Since he apparently comes back, I allowed him outside from then on. Since that moment, his behaviour inside has improved a lot. No more random play attacks on my ankles and hands, and generally much calmer.

He has also come back home with mice several times. He always eats them. So I think he is very used to living outside. Maybe been a stray, or a farm cat.

Forcing him to be inside would feel cruel.