His expression was still, stone-carved, pure concentration.

Level with fuming red nitric acid, of 98% pure concentration.

Spock's eyes were slits of pure concentration.

Those hours are pure technical concentration.

His demeanor was pure concentration - a surgeon tying off a capillary.

As an image of pure concentration, it is hard to forget.

We shall see Leonard likewise being 'diverted' from pure poetic concentration in order to achieve maximum hearing.

For the peace offered by pure concentration, for relief from all the doubts, he would have pledged any service.

It was a look she knew well, the mark of pure concentration, when the environment narrows down to one focus point: the kill.

The children were playing with Lego bricks and she often glanced over, awed by the look of pure concentration on their faces as they built.