Figure 3 shows how mounds and depressions (a) change into more commonly seen polygon (c) shapes. My photo in PART I shows gilgai that are in transition (b) in-between. In mature gilgai mounds are replaced by interconnected micro-ridges to create polygons. If you look at the aerial image at location (32.419913,-96.77876) dated 2-27-2001 you can see better developed polygonal gilgai in the yard behind the house. You can also see where contours have been plowed through the gilgai to help retain water and where the gilgai have been plowed flat in adjacent fields.
The development of salt polygons in desert environments appears to occur by an almost identical process as I describe here, except in the case of salt polygons the horizontal force is produced by the growth of salt crystals (see the textbook Geomorphology of Desert Environments (2009). This parallel process maybe the best supporting evidence for Ko >1 theory of gilgai.