What it teaches
The capitals of the countries the other world games already use, so the same twenty- three countries keep coming back with a different fact attached each time.
Capitals are pure paired-associate learning — there is nothing to work out, only something to know — which makes them the perfect thing to put on a spaced schedule.
How it works
A country is named and cities are offered. A missed pair returns tomorrow, then in three days, then a week, then three weeks.
Three levels change how many questions a round holds and how many cities are shown beside the right one.
What to look for
The wrong answers are other real capitals, which is what makes the game work: a child cannot pick the only city-sounding name, because they all are.