am taking my first group theory class and I find this the most confusing part. My rationale for this is that it is similar to a 4-gon.
The possible tranformations are $R_0, R_90, R_180, R_270$ (R is rotation),
Also, would this be an abelian group because rotation is commutative?
Thank you for any guidance. My current textbook does not have many examples on plane symmetries.