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.
As a rule of thumb the average backlash is defined as 0.04 divided by the diametral pitch; the minimum being 0.03 divided by the diametral pitch and the maximum 0.05 divided by the diametral pitch. In a gear train, backlash is cumulative.