writing twins

Actually, that would make them fraternal twins and not identical twins. Happens all the time and people don't notice because they think they're normal siblings.

This is in the context of books, but it is actually such an overdone trope that both Western media and anime share this in common in equal measure. The only exception I can think of right now are Rem and Ram, who look distinct enough, are different enough and are the opposite of troublemakers.