It just has to be some repetitive physical activity that doesn't require intense thought or mental focus. This can be chopping wood, taking a shower, walking, hiking, running, riding a bike, taking the dog for a walk, doing the dishes, etc. The key is: 1. No particular mental focus 2. Some kind of physical movement Your mind eventually starts to spin on autopilot, which is when it is able to mix things it can't while…
These are all games that require some type of intense focus but where I surely begin making mistakes the moment I consciously think about my actions in the game. Sometimes this means getting in the zone and not thinking about anything at all, but sometimes my mind is instead allowed to wander it a way it doesn't normally, and without judgment.