The ground became a flat wall in front of him.

She heard the scraping of her hand against the flat wall.

They continued in the same direction, hugging a flat wall with no further doors.

They came to a flat wall that might be the back side of a control panel.

The same thing can be done on a flat painted wall.

A human would use a roller here on this big flat wall.

I shouldn't have let them talk me into flat walls.

The lack of 90-degree corners and flat walls also adds to the work.

In the distance Richard could see colors flashing on a flat wall.

They stayed alongside the great flat wall of the trunk.