What shape do contour lines form to indicate a hill?

Contour lines that indicate a hill exhibit a pattern of concentric circles on a map. When observing these lines, the innermost circle represents the peak or summit of the hill, while the circles that surround it depict progressively lower elevations as you move outwards. This arrangement effectively conveys the three-dimensional shape of the terrain on a two-dimensional map.

The circular shape of these contour lines helps to visually communicate that the elevation rises to a point at the center, offering a clear representation of a hill's structure. The more closely spaced the contour lines are, the steeper the slope of the hill, while wider spacing indicates a gentler slope. Recognizing this specific pattern aids navigators in identifying elevation changes and land features quickly.

Other shapes, like hourglass or square formations, do not represent hills as they do not convey the gradual change in elevation characteristic of contour lines. Similarly, straight lines would indicate flat or uniform terrain rather than the varying elevations that define a hill.