You could make a decent argument that "flanking"- facing more than one enemy at once and "coverfire"-discouraging the enemy from being in good to effectively counter-attack always existed. Caveman attacks another caveman and one attacks on the back or side and the other side attacks on the front- the enemy was flanked. Caveman throws rocks at another group to keep them from getting their clubs out and whacking the first group giving the first group's side time to prepare. The fact that that such warfare bears little resemblance to automatic portable weapons the "tactic" was still there. If the next wave of technology modifies warfare- do you still say they are flanking even if the flanking shots actual kill the enemy or using cover-fire even though the cover-fire kill most of the side that cowering under cover that you are discouraging. You could say that tactic never disappears- even the magical Death Note has flanking and cover-fire aspects. When is a tactic gone and now its time for a new name? Some else posted effectively that 1916 "flanking" is same as 2016 flanking.