In future years, technology will add new layers of security.

What else can you do to add an extra layer of protection?

His life had started with pain and he'd been adding layers ever since.

"We didn't want to add another layer to the executive staff," she added.

The wetlands, which are to cost $150,000 to $200,000, will add a third layer to water treatment.

Why add a layer of friction to the system when it's not needed?

That would buy him some more time while he added extra layers of security behind it.

The next day or soon after, add a second layer of plaster level with the surface.

That would add an extra layer of protection in case you were to lose your key.

Then add another layer of tomatoes and juice on top.