Layer one on top of the other, and allow certain layers to be visible to certain types of devices.

将每个层放置在其他层的上面，并让某些层对于某些类型的设备是可见的。

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This is the layer that is most visible to users and application providers.

用户和应用程序供应商看到最多的就是这一层。

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You can create a visible grid to aid in page layout using the guidelines feature of your page layout software or by drawing lines or boxes that you place on a non-printing layer of your publication.

你可以创建可见的网格来辅助页面排版：你的页面排版软件有辅助线的功能，或者你可以在非打印层绘制边线或方块。

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The all-carbon formula doesn't need to be thickly spread to do its work, and it simply lets visible light through -- it could layer on top of a traditional solar cell to catch many more of the sun's rays.

ENGADGET: All-carbon solar cell draws power from near-infrared light, our energy future is literally that much brighter

So, this approach requires one more layer of effort: converting the height map (or at least its visible tiles) into a "normal map" which is smooth and natural enough to be subjected to lighting effects and then displayed on screen.

ENGADGET: Primed: The crazy science of GPU compute Mobile