Fig. 2. The rules for determination of the cell wall orientation in Plant- Layout. Representative examples of the cell wall orientation between the cells with the numbers i and j.

a, determination using the maximum and the minimum coordinates for the cell wall; b, determination using the angle between the major axis of the characteristic ellipse and x-axis; c, determination using the smallest rectangle containing the cell wall; d, determination using the common neighbor cell with the number q when the cell walls with numbers (i, q) and ( j, q) have the same directions; e, determination using the common neighbor cell with number q when the cell walls with numbers (i, q) and ( j, q) have different directions.