Many things in photography remain subtle for the sake of art. For this reason, lines in a scene don't have to be actual lines like a road, the seashore, or a tree branch. You can create implied or invisible lines by arranging similar elements in a line, like pebbles on a beach or the shoal of fish, and let the mind draw the rest.

Some common examples of invisible lines include:

• A repetition of elements, like trees, light posts, stars, people in a queue, etc.

• A person's gaze or a pointing finger that makes us unconsciously look in the same direction

Implied horizontal lines make the composition look stable and harmonious — for example, think of an alley of trees. Diagonals suggest motion and energy — think of an airplane taking off toward the sky. In turn, curved lines create a mood of peace, grace, and beauty — for example, a hilled landscape or a lily flower.