If a sheet of tissue grows uniformly, it may get larger or undergo an overall stretch in one direction. But if regions of the tissue grow at different rates or in different directions, the conflicts in growth lead to changes in outline and curvature. There are three types of conflict: Areal, Surface and Directional.
1. Areal conflict
Areal conflict is when different areas of a sheet try to grow or shrink at different rates. In the example below, the red region is trying to grow faster in area than the white region. This conflict in growth rates is resolved by the tissue buckling into a dome shape.
See Conflicts in action for another example of areal conflict with shrinking plastic.
2. Surface conflict
Surface conflict is when different surfaces of a sheet try to grow or shrink at different rates. In the example below, the red surface is trying to grow faster than the blue surface. The conflict is resolved by the tissue to folding.
Directional conflict is when regions of a sheet try to grow in different directions. In the example below, the green regions are trying to grow parallel to the arrows, whereas the purple regions are trying to grow at right right angles to the arrows. The conflict is resolved by the tissue buckling to form an elongated dome.