Android :: Activities And Tasks ?

I had a question regarding this concept. Suppose i have an application that defines a task. This task has some activities that belong to another Android application. The Dev guide says, that to maintain a uniform user experience, Android will maintain such 'distributed' activities as part of the same 'task' even if they belong to different applications.

I refer to it from here: http://developer.android.com/guide/topics/fundamentals.html

Some lines later, the Dev guide says and i quote: * * *"**Suppose, for instance, that the current task has four activities in its stack — three under the current activity. The user presses the HOME key, goes to the application launcher, and selects a new application (actually, a new task). The current task goes into the background and the root activity for the new task is displayed. The current task goes into the background and the root activity for the new task is displayed. Then, after a short period, the user goes back to the home screen and again selects the previous application (the previous task). That task, with all four activities in the stack, comes forward. When the user presses the BACK key, the screen does not display the activity the user just left (the root activity of the previous task). Rather, the activity on the top of the stack is removed and the previous activity in the same task is displayed."*

I think "three under the current activity" should be "four under the same task".

I think this paragraph i quote above has nothing to do with activities distributed across applications..and belonging to the same task. This para is maybe talking about two applications, that share a common application launcher and each application has defined its own tasks (stack of activities).

The user is simply toggling from one application to another, thus demonstrating that all activities (of a task) move together. However, the "three under the current activity" phrase is confusing me.