Omar Areny’s wife had left their 11th-floor apartment here only once in three days. When the power is out — which is often since the Israeli military knocked out nearly half of Gaza’s power supply on Wednesday — that means a long climb up the stairs. A Gaza beach, normally packed with sunbathers and swimmers in the summer, was relatively quiet Friday as Israelis continued to shell the strip. A boy takes a bag of flour from a distribution center in Gaza City. Aid groups are trying to supply emergency stores of food and other items. “It’s a prison but there are no guards,” said Mr. Areny, 40, waiting for the power to return as Israeli artillery shells thudded nearby on Friday. “You are obliged to stay in your house.” Full Story