Actually, when it shows the staircase of steps for the project, at the top it shows a small iPhone-like device that has tetris on it. It think it would be rather odd to just pull up some tetris variation from the app store on an iphone to put on there when it really has no relation to the project at hand (specifically, discussing nand2tetris.) It shows this twice, and it sounded to me like it was more than just simulations. I admit that I might have just gotten excited about the prospect of actually building such a gadget and mistook his words and meaning, but I am very certain that a device was shown during the nand2tetris segment on those stairs.
Also, thank you for linking that video, that is very interesting. I am just starting a computer engineering degree and I frequent TED so I found the Nand2Tetris video awhile ago. Now that I am starting to acquire information that would help me understand this, I was hoping to build this device. Although the device isn't part of it I still plan on doing the simulations, and hopefully sometime in the new few years I can make something to go with it. Anyways, thanks for the responses.