The Lenovo Thinkpad X1 Fold [Lenovo.com] is a 13.3" tablet with a folding 1560-line OLED display. There's a keyboard that magnetically clips into place, covering the bottom half of the screen and turning it into an ultraportable 6.65" laptop. It even comes with a pen, matching headphones and a leathery case. It's an amazing design, something right out of science fiction, and I'm eager to see if it's not terrible! The Verge's Monica Chin took a look.
The idea is that you can use the Fold like a large tablet when it's fully unfolded (or divide the screen into two adjacent displays). You can prop the Fold up horizontally to use it like a full 13-inch notebook, with an optional detachable keyboard and easel stand. You can fold the thing up 90 degrees, turn it vertically, and use it like a miniature laptop (a touchscreen keyboard pops up on the bottom half). You can turn it horizontally and use it like a book, with an optional stylus. Or you can fold the whole thing up, and easily carry it around without it taking up much space in your bag.
Now the downsides: it's $2,500 and the basic specifications (mobile i5, 8GB RAM) suggest it will struggle as a daily driver for anyone who works with photos, videos, dev tools or hurricane simulations.