These are engines,

"And this is the piston of the engines.
And this makes the crank shaft turn.
And the exhaust valve is closed.
And the intake valve opens.
Again, the turning crank shaft of the pistons.
Explodes again.

You have one power stroke.

Now, focus on this for just a second."

Girl : I can't even look at it anymore.

OMG. I LOVE PHYSICS.

+ MY DIRTY MIND.

HAHAAHAHAHAHA!

~DT