In the books, when Arya travels to Braavos and starts her training with the House of Black and White, she assumes the persona Cat of the Canals. There was disappointment when the show didnt follow that route, presumably to avoid any name-based confusion, and she went by the name Lana instead. However, there was still a nod to the characters unused identity, when shes explaining how every morning she walks the canals. Right as she says that, a cat runs across her path. Coincidence? I think not.