Watch This "Impossible Object" Dovetail Cube Puzzle

Kenjamoto // CC BY 3.0
Kenjamoto // CC BY 3.0

This puzzle is devious. Externally, it looks like a cube with dovetails cut on four sides—which should be impossible. Dovetail joints are normally cut to join two planes to each other, like the front of a drawer with its side. It shouldn't be possible to cut dovetails across four interlocking how does this puzzle do it?

You can just skip ahead to the video below if you'd like a visual explanation—or I'll spoil it for you now. In short, the "impossible dovetail" relies on a hidden set of diagonal cuts that allow the puzzle to slide apart diagonally. There's often a pin or other fastening mechanism to prevent an accidental slide, making the joints appear firm and fast until you press it.

The logic of this puzzle plays on our assumptions about how dovetail joints work. Because these joints typically prevent motion in two planes, those are the planes we look at. Is it possible to pull the top off the puzzle? Nope! How about side-to-side? Impossible! By adding a dimension to the puzzle, the solution is revealed in that extra dimension as well—you've got to slide the pieces apart diagonally. The joints, of course, aren't's our assumptions about how dovetail joints are cut that are incorrect.

In this video, "Mr. Puzzle" walks us through the solution to a wooden version of the puzzle (the solution starts at 1:52). Have a look:

If you're curious how this thing was made, here's a similar project by Clickspring, but machined out of aluminum. Behold:

If you'd like to make your own puzzle, free plans are online for a wooden version (requires a hand saw, coping saw, and chisel) as well as a plastic version (requires 3D printer).

(Image by Kenjamoto // CC BY 3.0.)

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The Truth Behind Italy's Abandoned 'Ghost Mansion'

YouTube/Atlas Obscura
YouTube/Atlas Obscura

The forests east of Lake Como, Italy, are home to a foreboding ruin. Some call it the Casa Delle Streghe (House of Witches), or the Red House, after the patches of rust-colored paint that still coat parts of the exterior. Its most common nickname, however, is the Ghost Mansion.

Since its construction in the 1850s, the mansion—officially known as the Villa De Vecchi—has reportedly been the site of a string of tragedies, including the murder of the family of the Italian count who built it, as well as the count's suicide. It's also said that everyone's favorite occultist, Aleister Crowley, visited in the 1920s, leading to a succession of satanic rituals and orgies. By the 1960s, the mansion was abandoned, and since then both nature and vandals have helped the house fall into dangerous decay. The only permanent residents are said to be a small army of ghosts, who especially love to play the mansion's piano at night—even though it's long since been smashed to bits.

The intrepid explorers of Atlas Obscura recently visited the mansion and interviewed Giuseppe Negri, whose grandfather and great-grandfather were gardeners there. See what he thinks of the legends, and the reality behind the mansion, in the video below.