3 images overlap, and how to select the middle that picture

There are some subview (image) on the view, one image is a box, is a cover (lid on the box, when you can touch the switch), there is an object, you can touch and move. I now open the lid, put the object and drag it to the box, and then close the lid, the lid has a transparent effect, you can see the box objects. You can select an object and drag the box out.

My question is how to select the three image overlap when the object is in the second layer. I am a novice, newly developed three months, please advise, thank you!
Reply:
1, CALayer / view penetrate

2, event map
Reply:
Do not quite understand how to penetrate, please give me an example

cited a floor ybh37 reply:

1, CALayer / view penetrate

2, event map

Reply:
In xib files that File's Owner is located in the middle of the window click on the above list mode can point to expand the list goes on the middle
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Passing, then points.
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The top view to get a touch event, reached the next level