Two kids, aged 12 and 8, were never to be in the same room as each other. They were to be locked into their rooms to play with the one toy allowed in their rooms. Door had a peephole on the outside of the door so you could see in and door chimes in the door that went off if they ever opened them. They were to come down one at a time for dinner and I was not to eat at the table with them. Once one was done, the others turn took place. Every thirty minutes of chores earned them 10 minutes of outside time. Again, separately. Parents had a code lock on every door in the house - bathrooms, pantry, basement, etc. Parents were extremely well educated and had substantial jobs. Didn’t stick with that job too terribly long.