As you will learn during one of the single-player missions, Prism Towers can be placed in close proximity to one another to increase their power. This is similar to the way the Soviets place Tesla troopers adjacent to Tesla coils to increase the defensive structure's power. Careful placement of Prism Towers can increase their potency by tremendously. Use the map's landscape to your advantage when forming your base. Leave only a few available entrances and defend these with a few Prism Towers in close proximity to one another to increase their power.