A Venn diagram is a way to represent a set of things. Picture a circle, with a name (commonly a capital letter), filled with things, elements. They can vary from being letters or numbers to words and strings. They can be anything, and the set itself is formed because all those elements have something in common.
Say there’s a set named “Alphabet”, the elements being a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y and z. What do they have in common? I think that’s pretty obvious. Now imagine a person, as a whole, could be its own set, its own Venn diagram. The name would be the person’s name and the elements any knowledge, thought, emotion, feeling the person have. The diagram is filled day after day with new things. Nothing leaves the diagram. You grow as a person, and from that you, as a Venn diagram, grow, too.