( Previously we folded and then drew a line. But here we want to do in reverse. Do you know why? The reason is we will not unfold the four corners)
16.
Do the diagonal valley-folding along any one red line shown in the step #15.
The Useless Tree
Hui Tzu said to Chang Tzu, "I have a large tree which no carpenter can cut into lumber. Its branches and trunk are crooked and rough, covered with bumps and depressions. No builder would turn his head to look at it. Your teachings are the same-useless, without value. Therefore, no one pays attention to them." "As you know," Chuang Tzu replied, "a cat is very skilled at capturing its prey. Crouching low, it can leap in any direction, pursuing whatever it is after. But when its attention is focused on such things, it can be easily caught with a net. On the other hand, a huge yak is not easily caught or overcome. It stands like a stone, or a cloud in the sky. But for all its strength, it cannot catch a mouse. You complain that your tree is not valuable as lumber, but you could make use of the shade it provides, rest under its sheltering branches, and stroll beneath it, admiring its character and appearance. Since it would not be endangered by an axe, what could threaten its existence? It is useless to you only because you want to make it into something else and do not use it in its proper way."
