Let's say you're on some spot on a side street that projects from a main cathedral square, and you want to get to another point on a side street just like that.
假设你处在一条小巷的某一点上，这条小巷 是从天主堂广场延伸出来的，而你想去 另一个地方，它处于另一条从那广场延伸出来的小巷上。