For example, a simple number guessing card helps you to guess people's age correctly and astound them, by using the concept of binary numbers.
而張世宗打算利用拓樸原理，把一些深奧的數學觀念寓於簡單好玩的遊戲中，譬如拿猜數卡猜中別人年齡，引起驚訝時，就可以藉此帶出二進位的觀念。