Here is a post from August 2016. After almost nine years together, Frankie and Floki still play regularly. Floki chases Frankie in one direction, then they switch, and Frankie chases Floki the other way.
Bad Cat Chris
The Baddest Cat You'll Ever Love
Bad Cat Chris 
Frankie is so sweet. No hisses. No swipes. Just gets up and walks away.
Sometimes he is good.
doodz…..itz grate ta haza buddy N playmate N pal N brother !!! ☺☺ ☺☺♥
Floki is lucky.
Playing with the tail is true brotherly love
Only a brother will put up with it.
Playmates are always a good thing!
A very good thing.
It’s good they play with each other this way.
We once bottle raised a kitten which ended up living with a small dog, and they would do the same thing. The cat would chase the dog through the house, they would both slide on the wood floor of the hall and thump into the wall, then scrabble themselves up and the dog would chase the cat the other way, back and forth until they were tired and would nap together.
It like having two three year olds. 🙂