What is the reason for color of lines are repeating?

I was run richards program. This program was run successfully but I am not clear about graphs. Because many number of lines are plotted here and also same color are shown what is meant by repeat colors. Please give some possible solution.

Answer 1

[Mischa Kim]

Venkatesan, could be that there is a

 hold on

command, somewhere in the code? If so, replace by

 hold all

to get differently colored line plots.

Answer 2

[Image Analyst]

There is a set of default colors for lines and once they're all used, the colors will repeat. So if you have many lines, there may be repeated colors. See my demo, attached below in clue, on changing the default color order.