Clouds are not spheres, mountains are not cones, coastlines are not circles,
and bark is not smooth, nor does lightning travel in a straight line.
From: Mandelbrot 《The Fractal Geometry of Nature》
云不是球体, 山不是圆锥体, 海岸线不是圆的, 树皮不是光滑的, 闪电传播的路径也不是直线.
—— 曼德伯罗特《大自然的分形几何》第一章
谢楼主好书. 补个书荐, 引用得较多