Linear And Curvilinear Boundaries

 

Consider a cricket ball for an example. If we try to plot two points and try to join them using a straight line, we will fail. Yes, two points on a cricket ball cannot be joined using a straight line, it will be only a curve. So, the distance between these two points is curvilinear. Whereas consider an example of a cylinder. There are chances to connect the two points using straight line or curve. Hence linear as well as curvilinear are possible.