People in front of waterfront, 3 people are sitting down facing each other as a young boy runs and 2 people walk towards the water.
3 people are seated with their backs against each other
the people cannot be  facing each other and also have their backs against each other.
They are facing each other, so can not have their backs against each other.
The people cannot be sitting facing each other and with the backs against each other at the same time.