Hi,

you can get the indices of all the sites in the finialized system by using the `sites`

property of finalized systems. After that , it's just a case of writing a function that

can filter this list based on whether a site is on the `edge` or not. You would have

to define this filtering yourself. For graphene I would imagine that such a filter would

involve querying the number of neighbours of a particular site.

Happy Kwanting,

Joe