Table 1.

Overview of the nonaccidental and metric changes used in this study

Nonaccidental changes	Metric changes
Straight main axis versus curved main axis (Fig.3A)	Degree of curvature of the main axis
Parallel sides versus nonparallel sides (produced by expansion of the cross section) (Fig. 3B)	Amount of expansion of the cross section
Straight sides versus curved sides along the major axis (with positive or negative curvature) (Fig.3C,D)	Degree of positive or negative curvature of the sides
Curved versus straight cross section (e.g., a cylinder becomes a brick and vice versa, or a cone becomes a pyramid and vice versa)	Changes in aspect-ratio; a part of an object can vary in length or width, or it can be stretched, becoming wider and shorter or narrower and longer
The cross section ends in a point versus the cross section ends in a side (e.g., a cylinder or brick with expanding cross section becomes a cone or a pyramid or vice versa) (Fig.3E)