Figure 5. Plan view ( 1 ) and rose diagram ( 2 ) of the orientation of the long axes of the horizontal, regularly-oriented structures in the Clarens Formation of southern Africa. Note that at locations 3 and 6, the mean vectors (arrowed lines) in successive stratigraphic units lie at right angles to each other (see pairs of grey and black stars in 2 ). 3 ) A field example of the above case, shows a step-like cliff face in plan view, capturing two successive horizontal surfaces in which the structures are at right angles to one another.