11.   The higher frequency bypasses most interference and lets the signal penetrate walls better than the current generation of cordless phones.

12.   There is no traffic light for a hundred miles, and talk radio cannot penetrate the walls of the Big Ditch.

13.   The water apparently dripped down from upper to lower basilica without penetrating the walls, the Italian news agnecy ANSA said.

14.   Sub-machine-gun bullets failed to penetrate the walls while grenades detonated on top of or beside igloos failed to make any effect.