Books are like people, in that they need to lean on each other for support. When you remove a book from a shelf, or from between two bookends, the neighboring books close the gap by leaning.

While aesthetically displeasing, leaning books isn't a huge problem for most of us. But unsurprisingly a designer in Japan—a country obsessed with UX—has designed a way around this. This Firm Book End, from stationery brand Lihit Lab, allows books and other book-shaped media to stand on their own.

The flip-down stoppers are gravity-activated. Units can be linked side to side, allowing users to select the overall length. Rubber feet on the bottom prevent the unit from sliding.

The one shown above is A5 size, and there's a larger A4 version too, shown below.

The A5 runs ¥1,300 (USD $9) , and the A4 is ¥2,300 (USD $15).