When Ibrahim Farahat awoke to discover a large yellow concrete block on his doorstep in Gaza City, he suddenly found himself right on the perilous demarcation line marking the withdrawal of Israeli troops. "They placed the yellow block in front of our house. It was previously near the Al-Aqsa pharmacy," about a kilometre away (less than a mile), Farahat tells AFP. Several residents of the Shujaiya neighbourhood, east of Gaza City, told AFP that they had found such blocks around their homes -- which they believed had been placed by Israeli forces overnight between Thursday and Friday. IMAGES AND SOUNDBITES