And now the invisible boundary had been passed.

However, they are often confined to one part of the game world by invisible boundaries.

She waited in stillness until he crossed some invisible boundary.

Beyond its invisible boundaries, neither matter nor energy could ever hope to escape.

He had marked the invisible boundaries with his scent, and patrolled them regularly.

She quivered at the threshold, as if held by an invisible boundary.

He hesitated at the edge of the garden, for the baboons had long since learned to respect that invisible boundary.

He is critical of games that claim to offer freedom, but present limits or invisible boundaries where players do not expect them.

Try as he might, he could not break past the invisible boundary that hemmed him in.

On his return, he found that the flock had not left the invisible boundary.