This has been represented in Figure 1 by drawing an actor inside of the system which is acting with another system.
在图1中，表示它的方法是把参与者画在参与另一个系统的系统中。
2
In the drawing is the directory structure that maps to the disk system.
在图中，目录结构映射到磁盘系统。
3
But because your visual system interprets the two-dimensional drawing as three-dimensional reality, you see the right side "in shade" and so perceive the right-side dot as bright, even glowing.