They are.

She is the little smile on her lips.
She is the laugh at funny jokes.
The country music in the city.
The pop music in the middle of know where.
She is the skip in her step,
The tune on her tongue,
The song in her heart.

He is the old jersey's on the wall.
He is the color orange, like the sun.
The game system on the floor.
The posters on the wall.
He is the smirk on his lips,
The chess set on the dresser,
The movies on the shelf.

They are two big parts of a whole puzzle.

She is the music created by her finger tips.
The way a simple compliment makes her light up.
She is the rough housing,
The cuddling.
She is the caring hugs.
She is the upset tears.
The late night video game sessions.
The early morning shopping trips.

He is the smell of cologne in the morning.
The corny jokes that always seem to make someone laugh.
He is the arguing.
The apologizing.
He is the caring hugs.
He is the upset tears.
The hours spent on his game system with friends.
The days away from home.

They are siblings, as different as the sun and moon.
But as similar as the stars above.