Here is a pic from the recent Battle For Salvation tourney where I went 3 for 3 with my Necron list showing the idea of wall tactics flawlessly. The idea is to use the monolith as a “capstone” in the center of the table and to then use your opponent’s vehicles or drop pods, in this case pods, to build a wall in front of your Necron core. I’m also using terrain, in the case of the pic the tower to the left, to further extend the wall. By NOT destroying the drop pods my opponent can’t roll vehicles up through them and I’m getting cover saves from his incoming shots. Not having any AP1/2/3 shots of my own I don’t have to worry about cover saves on the marines. It also allows for a nice funnel for my lord and C’Tan to assault. Think hot gates in action, where in the case of this pic forty nine Necrons held off eighty marines- almost a battle company! THAT is the power of the Star Gods!