There are other method of contouring like the arithmetic estimation, but for less accurate but quick draw, one can use their fine judgement and free hand technique to draw the contours for the given elevation points. In the following example, the control points are already drawn. The square patterned control points' elevations are shown, one has to use the fine judgement to draw the contour lines. See how it is done, all you have to do is to judge the contour line's placement from the given elevations.
Look at the nearest control point elevations. If the nearby elevation is higher, then the terrain is rising towards it, if it is lower, terrain must have a downward gradient. Definitely the higher contour must lie towards the rising terrain and a contour with the lower elevation must lie towards the downward gradient.
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