i'm not sure how to answer this question. can some one help me on this as soon as possible. thanks

Exercise: Give a concrete counter-example of the diamond property for one-step beta reduction. You're looking for a case where reversing the order of just two redexes results in two different lambda expressions after two steps.

- Answers, there are two. comment: this is the part B of the problem. I dont know how to answer it 

(b) Consider the lambda expression: (\x.xx) ( (\x.y) z ) Show that lambda expression does not obey the one-step diamond property.