Another Word question!

You know you all love it when I ask how to drive Word. Today's question is: what are the little black squares in the following screenshot? The Help is unhelpful. Update: Solved thanks to scat0324; they're “keep with next” markers.



(I know what the paragraph marks are, it's just the squares. This is Word 2004 for Mac, Version 11.0 (040408) on OS X 10.4.3.)