[thaumasiotes]

> how many lines do we need to draw to give the impression of a person, or a tree?

Context sensitive, but yes, surprisingly few.

大 is three lines.

木 is four.

[inimino]

人 is just two.

[thaumasiotes]

I'm aware, but you need special training before you can recognize that as a person. 木 is "wood" in the modern day; does 树 really make you think "that looks like a tree"?

[inimino]

So perhaps any visual representation of meaning would require shared context to interpret, and would then inevitably become symbolic rather than directly representational.

[thaumasiotes]

I don't understand what you're trying to say here, but e.g. Michelangelo's David is widely recognized as representing a person, and no shared context is required for that.