Curious cat figuring out how to use the cat door

Cats are smart and curious creatures and they are fast learners too! We had moved to a new home and Rusty wanted to go outside and explore the new territory. But he had to conquer the cat door first! He'd never seen one of those before, and I had to show him that it was actually a way out to the backyard. He'd sit there staring at it for a couple of days, but never gave up! So he took his time, studied the enemy and eventually found his way out! Persistence is the key to success after all! Go, Rusty!