I went to a site with some mystery... and there...

Believe it or not, the reader is right, but on the number 7 (seven) the human world is built. He stands on it, like on a tectonic plate, and ideologically relies on it, seeing in it the root of everything. For visibility: in the human world there are 7 colors, 7 notes, 7 days a week, 7 periods in the table of elements, 7 measurements in string theory and even 7 fingers on the hands.

O_O