Why are Gaussian distributions everywhere?

&gt; <i>The trick is that a normal distribution occurs when you sum independent, symmetric distributions.</i><p>It&#x27;s not neccesary that the distribution is symmetric. You can try for example with 500 genes witn 10% of 0.00 extra height and 90% of 0.01 extra height. You will get again a gaussian but the center will be in 500*(.10*0.00+.90*0.01).

tl;dr: Gaussians show up when you add together enough small random effects. The notebook has some code and prose that shows why that&#x27;s the case both for human height and for manufacturing wooden doors.