11.   This leads to modular programs.

12.   Data abstraction builds a wall between the user of some data and the representation of the data using the operations on the data as the interface.

13.   So he might get his wall built but he might have to wait a year before he starts it.

14.   And even if policy makers wanted to, it might well be impossible to build walls around the country.

15.   And then you start building the walls.

16.   As kids build walls, adoptive parents struggle with their own uncertainties.

17.   As a result, officials have built higher walls to shield the tents housing new troops.

18.   As a Web designer, I do not consciously build walls, but like the architect of my office building, I do fall prey to vanity.

19.   As the Germans moved closer, Drouhin built a wall to protect his best stuff.

20.   At the very moment America praises Robinson and Woods for smashing barriers, it is building new walls that will leave most African-Americans segregated and shattered.