Either write one or look online for one.
You should do your own homework. Eventually, you will be asked about this either by your teacher or on a test and if you have someone else do your homework, you will flunk both. It'd be best to write this yourself.
Here's an alliterated 12 liner .You'll have to search for assonance and consonance yourself. Maybe next time you could ask for examples of onomatopoeia: It's lots more fun.
Mr. See owned a saw.
And Mr. Soar owned a seesaw.
Now See’s saw sawed Soar’s seesaw
Before Soar saw See,
Which made Soar sore.
Had Soar seen See’s saw
Before See sawed Soar’s seesaw,
See’s saw would not have sawed
So See’s saw sawed Soar’s seesaw.
But it was sad to see Soar so sore
Just because See’s saw sawed Soar’s seesaw!
No, THAT is not what you "need" .. What you DO need is to learn to use your own literary skills .. Something that THIS task is meant to exercise.