Relax and aim your eyes further into the distance. Let your eyes drift outward and make the two middle dots slide towards each other until they merge or overlap. If you can't get the inside dots to move towards each other, you need to relax your eye muscles more. Look farther into the distance. Imagine you are looking at a sailboat way out on the ocean.
Many kids master the skill of crossing their eyes in order to impress family or friends.
If so, cross-viewing is right up your alley. Well, not as much as those goofy kids. Bring your forefinger up about six inches in front of your nose. Focus both your eyes on your finger. Still focusing on your finger, notice what has happened to the dots on the screen.