Boyer - 28 
I ' \ ■ S 
.(c) (d) 
Figure 64: The second level preattentive organizations, (a) Parallel symmetries (b) 
Continuous (symmetry) lines (c) Strands of symmetry axes (d) Clusters of similar 
features. Each feature is represented as a dot and lines are drawn between similar 
features. (Note that the images have been reduced for display.)