I've got twins in one of my classes. I've taught lots of sets of identical twins and can usually find a subtle way to tell the difference between them, but this pair have me stumped. Their parents can't really tell me how to easily tell them apart.
If they are both talking to me, one has a slightly higher voice, but that's no good if I'm only speaking to one. No freckles etc in particular places that help me tell.
Their friends are equally stumped. And have taken to referring to them by tacking the word 'twin' onto their surname. E.g. It's one of the Twingletons.
I've asked them if they mind. One does. One doesn't. I don't think I'd like it.