The lines in this ad for the Obama election of '08 are horizontal and curved, which means stability and restfullness.  The lines are inside a circle which could mean either infinity or protectiveness.  The colors of these lines are the same colors as the Flag of the United States of America, so the makers of this ad are trying to portray the above qualities to the United States if Obama were to have been elected.  The sizes of these line seems to be moving from the left to the right.  That could be representing the USA moving forward.

The curved lines in the National Survey of Student Engagement make the image look graceful, and the triangular formation suggests movement like its spinning.  The circles are inside the curved triangle, which means protectiveness since its not the other way around.