As in north Africa there were no natural obstacles,The DAK pioneers became masters in making the mine fields; for example, during their retreat from El Alamein, they sometimes put under the ground tin cans. The british then found the cans with the metal detectors and thought it was a joke the germans made to slow their advance, so they let the tanks go on.....And they blew up because after a few meters of tin cans there were the real mines. The germans also invented a kind of psychological tricks in the village houses. For example, a crooked painting : a simple soldier wouldn' t have minded of that, but a british officier would put it in the right position...And boom.