Sounds like homework. What do you have so far?
What I think is happening: you pick random points for each point... you need to pick one set of random points for each blade of grass.

try using a for loop so you dont need 500 lines of code. try creating a bounds for the random() call. use these pages for help: 

Note on subject: that's better (you describe your objective) but the "need help" is redundant...
See https://forum.processing.org/topic/where-to-place-threads-and-other-forum-practices
Note I move your topics to General Discussion because Programming Questions are more for questions about your code, so we can help you in improving it. So far, most of your messages were to paste the assignment and wait for somebody to do it for you...
Your message suggests you tried to do something. Don't be afraid to show your code (like for the cow), we can show you how to improve it.

andrewgies17, that's the right amount of help: not giving code right away, but pointing how to do things and where to find references.