3 “high IQ meme guys” inhabit widely different body-heights on a normal distribution, which uses the Body height as the sample space.

Body Height is normally distributed. https://www.johndcook.com/blog/mixture_distribution/ https://de.wikipedia.org/wiki/Datei:Körpergröße.png

The joke: IQ and Body-Height are unrelated, but both IQ and body height follow the normal distribution: IQ by definition and body height does so by empirically measuring it (since random variables that control body height are summed up to arrive at the outcome).