I once had a cat named Aleister (named after the infamous Aleister Crowley!) who was just about as smart as this one.
I watched Aleister, one day (unbeknownst to him!), try to sneakily open our back door, which was a set of sliding glass doors.
1. He pulled out the stick I had placed in the floor crack (for safety against break-ins) with his paw.
2. Then he jumped to the bookshelf near the door (right at handle height).
3. Then he leaned over and unlocked the latch on the door with his paw.
4. Then he used both paws to try to slide the door open.
I was both amazed and aghast. Holy Cow. This was some smart cat. Fortunately, his little body wasn't strong enough to get the door to slide open. But WOW.
Then there's this little guy. ENJOY!