Best example I heard of this was from a Sunday School teacher. She was teaching her young students about the holy Trinity.
"You all know how an egg is one thing, but like the father, son, and holy ghost, it is actually three things. There's the shell, that's one thing. Then there's the egg white. That's another thing. And the final thing is the yolk. Three in one."
To demonstrate this, she then cracked the egg open for her class to see.
It was a double yolk egg.
Proof to me there is a God and he's got a sick sense of humor.