Soldiers and Marines in defensive battle positions routinely use wooden or metal "aiming stakes" to mark the limits of their sector of fire and to mark other key points (their principle axis of fire when in the decisive phase of the engagement, or key points such as a trail junction or bridge). During periods of low visibility (night, or after enemy artillery drops smoke shells) the soldier can use the stakes to determine where to place his weapon. The problem is that aiming stakes rarely work properly. The soldier either has to bring something to use (e.g., metal tent pegs, pre-cut wooden stakes) or cut locally available tree branches and brush to produce them. This can be difficult in a desert where there are no trees. A better solution would be for each soldier to bring several empty sandbags. These can be filled on the spot (and emptied when it is time to move). A stack of two sandbags marks the limit of the soldier's assigned field of fire, while single sandbags mark key targets or the final defensive fire axis. --Stephen V Cole