"Self-healing" minefields can move around in response to enemy activity. According to the article, "The munitions of the 'Self-Healing Minefield Program' use tiny radios and acoustic sensors to stay in constant communication with each other. If some of the mines are removed, the ones that remain can 'hop' hundreds of meters away, if needed, to rearrange themselves and to close the gaps. 'The minefield acts more like a fluid, and less like a static obstacle'..." More information here.