The diet side of it is good to be partly genetics. You don't have any control over there your body desires fat. If you're lucky, it's going to be spread all over, so with a little weight gain you wouldn't see stuff like that. On the other hand, if your body primarily stores fat in your belly, you'd have to gain a lot to see a difference in your ribs.

For the exercise part, look up exercises for oblique and serratus muscles.

Lol, you should focus on your brain loser.