The brother-sister-get-married patternflood mythology has always been taking as the evidence of consanguineous marriage, which is a misinterpretation.
兄妹婚型洪水神话历来被视为是人类早期存在过血缘婚阶段的重要论据。
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The pioneering chaos theorist Benoit Mandelbrot found that annual flood levels of the Nile follow this pattern; others have observed it in music and air turbulence.
If pattern arrangement is irrational, fracture is in adverse orientation, serious consequence such as early water breakthrough, even burst water flood will happen to producing well.