In the video, a young woman offers two children a problem: How many paths are there between two points on a square, where point S is on one corner and point G is on the opposite corner, and you can only travel along the lines of the square? The answer is simple: 2.
The young woman then divides the square into 2x2 and asks the same question, adding the caveat that while you can travel along the lines of the square any way you want, you cannot travel the same line twice. By counting each path, she shows that there are 12 ways to get from point S to point G.
She then moves on to divide the square into 3x3 and through the same method determines that the number of possible paths has increased to 184. In this way, the young woman shows that by dividing the square into more and more squares, you increase the number of possible paths exponentially. Educational, isn't it? But she doesn't stop there. What started out as a simple demonstration quickly becomes a journey into insanity as… Well, just watch for yourselves…
The video is subtitled so don't worry about not understanding Japanese.