The most serious problem in information flow arises when the delay in feedback is exactly one-half cycle, for then the corrective action is superimposed on a variation from norm which, at that moment, is in the same direction as that of the correction. This causes the system to overcorrect, and then if the reverse adjustment is made out of cycle, to correct too much in the other direction, and so on until the system fluctuates ("oscillates") out of control. This phenomenon is illustrated in Figure 1. “Oscillation and Feedback”. If, at Point A, the trend below standard is recognized and new inputs are added, but not until Point B, the system will overreact and go beyond the allowable limits. Again, if this is recognized at Point C, but inputs are not withdrawn until Point D, it will cause the system to drop below the lower limit of allowable variation.