Look at the lines I've circled. They connect 1 block of pattern to the next. You can repeat the pattern any number of times using these connecting lines. These lines dictate why and where you should take a side-trip.
Now, let's examine each sample in turn.
Sample 1: The purple portion, below the connecting line, in the first section of the pattern, leads to a dead end and so, it can only be a side-trip. All the purple lines are dead ends. This decides the path the main journey should take.