Imagine you're standing at a bus stop and the Red Dawn siren suddenly blares, indicating you have 15 seconds to find cover before a Kassam rocket hits. Residents of Moshav Netiv Ha'asara can now bolt for a specially constructed, prefabricated, reinforced-concrete shelter in the parking lot, where they will be safe from flying shrapnel. The IDF has dubbed these structures "cubes" and plans to distribute them shortly in Sderot and on the campus of the Sapir College adjacent to Sderot, as well. They are one of the ad-hoc solutions the Home Front Command has installed to protect the residents of the communities surrounding the Gaza Strip from Palestinian attacks. The IDF has been working at a feverish pace to provide these communities with a security envelope that includes electronic fences, high cement barriers against snipers and reinforced roofs for kindergartens and classrooms. According to Col. Yehiel Cooperstein, head of the physical protection branch of the Home Front Command, the IDF has nearly completed the protection of Netiv Ha'asara, a few hundred meters north of the Gaza Strip. He pointed out a 170-meter-long cement wall and another one, half a kilometer long, running alongside the heavily guarded border road. "We used computers to analyze the firing lines and have placed these walls so that the Palestinians can't hit any of the residents here," Cooperstein said. He said the barrier cost "tens of millions of shekels," adding, "and if the Palestinians build a tower, then we have a problem." While the barrier addresses the immediate threat of direct gunfire, the Home Front Command tackled the threat of mortar and Kassam rockets by attaching security rooms hauled out of Gush Katif ripped off the sides of homes to Netiv Ha'asara homes. So far 114 repainted security rooms have been installed. The price tag for each is about NIS 55,000; the army installed them free of charge. Below the moshav is what the Home Front refers to as "the little city," where it has collected some 150 of the 40-ton reinforced rooms for distribution as needed. Further south is "the big city," where the IDF has stored about 70 larger, reinforced classrooms, taken out of Gush Katif schools. Cooperstein said the IDF had identified Netiv Ha'asara, Kibbutz Nahal Oz and Kibbutz Kerem Shalom as "borderline," the most vulnerable to infiltration and attacks. For the latter two, protection similar to Netiv Ha'asara's is being installed, Cooperstein said. In addition to this, the army is erecting special roofs on the kindergartens that will safely detonate incoming rounds and rockets. He complained that efforts to complete the protective envelope were held up by the residents themselves, who took a long time to actually believe the disengagement from the Gaza Strip would take place. Sketching a map of the Gaza region in the sand, the colonel drew two sweeping lines from the Gaza Strip across to the city of Sderot. "This is the estimated corridor of Kassam rocket attacks," he said. In this zone, the army has already reinforced the roofs of five kindergartens and is about to start work on nine more. It has also demolished 11 schools and, together with the Education Ministry, is rebuilding reinforced schools in their place, which was deemed a cheaper option. Visiting the Sapir College on Thursday afternoon, the Home Front Command officers discussed the erection of special pergolas designed to detonate incoming Kassam rockets. The army is to provide the campus which includes an elementary school, junior high and high school with a dozen reinforced classrooms that had previously been in Gush Katif. Living under the threat of Kassam rockets or mortar rounds crashing suddenly through the roof has led the school to move some classes into bomb shelters. "We don't keep them in here for more than two hours, maximum," said elementary school principal Anat Regev. "After that they don't feel well. There's not enough air." So far, the Home Front Command has spent all of the NIS 85 million budgeted for protection. While the policy of warning residents of incoming Kassam rockets and providing them with reinforced cover that answers that threat, the military sources admitted that residents were still vulnerable to mortar strikes since there was not yet any radar system capable of warning of such an attack. Military sources are also concerned the introduction of 122 mm. Katyushas on the scene would not only make the protection less effective; it would also greatly increase the number of Israelis under threat since Ashkelon would be in range.