Thinking is generally thought of as doing nothing in a production-oriented society, and doing nothing is hard to do. It's best done by disguising it as doing something, and the something closest to doing nothing is walking.

青竹 云海 晨光 星夜 荷风 晴雪 秋山 听海 沙丘 森语 梅影 花野 听雨 晴窗 暮色 橘光