Blue is the color of the sky and sea. It is often associated with depth and stability. It symbolizes trust, loyalty, wisdom, confidence, intelligence, faith, truth, and heaven. Blue is considered beneficial to the mind and body. It slows human metabolism and produces a calming effect.
1 Backlash (sociology), an adverse reaction to something that has gained prominence.  Backlash (pressure group), a UK group opposing the 2008 law criminalising possession of extreme pornography.
Backlash is defined as the amount by which width of tooth space exceeds the tooth thickness of engaged gear when measured on pitch circle. Now, it is clear that when this happens there is some gap left between the teeth engaged.