Eyes, and their really weird focus illusions

Hello!
I have an activity for you this time (not that long or big, won't take you more than a few seconds).
Close one of your eyes with your palm. Go to the grill of your window, and focus on the grill. You may observe that you can't see what's behind it. Now, focus on the background.

It'll be quite a shock when you can actually, really see what's right behind what you couldn't see without moving an inch!

It is very, very weird, and certainly a bit undecipherable.

Here's a list of possibilities, of how the eye could've seen behind:-

1. The human eye is divided into several sections, and some of the sections start turning to look where some other sections can't see, automatically helping us. It works only in close objects because the human eye isn't an aye-aye.
2. The human eye might be concave, making us a have a little lesser optic range than that if it was convex. It focuses from all directions.
3. The pole was scared and moved :-)

When you out-focus an object close to you, it appears like as if the object has thinned hazily.

Any ideas?