True, although they are quite content to make up puzzles all their own. Leave out a sealed plastic container of dry kibble, and they will find a way to break into it.
We keep cat treats in a kitchen cabinet. I have one cat that knows exactly where they are. He jumps on the counter and stretches to reach the cabinet door and opens the door just enough so that when it closes it makes a thump. He's telling me that I should give him treats. I am certain he could get them himself, but he wants his human servant to do his job. He seems rather upset when I don't read his mind and he has to go through all that effort for me to give him is treats.