Conventional Art is very, well, conventional:
That’s a painting of a bowl of fruit.
It looks like a bowl of fruit.
The artist intended it to look like a bowl of fruit.
Everybody who sees it can tell that it’s (say it with me now) a bowl of fruit.
Contemporary Art is different:
That could be a bowl of fruit – or it could be various snakes of different colors who’ve just devoured a pack of rats, then curled up together in this bowl, their skins distended into vaguely fruit-like shapes by the currently-being-digested lumps.
Or maybe it’s a horse.