At some point I'd begun to enter the murky area where the boundary between the human's issues and the dog's troubles blur.

The sky islands exist as a sort of biological Nafta, where national boundaries blur.

The list goes on, and at a certain point the boundaries of these different restaurants blur.

The boundaries between these system definitions are blurring as time goes on.

If theoretical boundaries are blurring, it may be because policies have done the same.

The really tough part of this is that the boundaries between internal and external constituencies have blurred.

The boundaries between local and long-distance services are already blurring.

But as jobs and technology become more complex, the boundaries have blurred.

At the same time, the boundaries between that body of work and his adult plays have become increasingly blurred.

But this is a time when the boundaries between science and engineering are blurring.