The Impossible Dovetail Puzzles by Wil Strijbos

Updated: Aug 5

Wil Strijbos (short for “William”) is a Dutch puzzle designer famous for his particular brand of finely crafted anodized metal puzzles. These are usually either assembly, disassembly or sequential movement puzzles. Beyond metal puzzles, Wil also invented award-winning wooden puzzles during his younger days. He won the Hikimi Wooden Puzzle competition in 1990 with his puzzle “Just Fit” and earned second place in the 1994 edition with the puzzle “Anti Slide”.

In this article, we take a look at a set of three brilliant puzzles by him in our collection: the Impossible Dovetail Puzzles!

Image taken from puzzlescore

Their polished, clean-cut, simplistic design belies the ingenious engineering that has gone into each puzzle. The goal of each puzzle is simple: remove the green piece from the aluminium block it is embedded in. Wil started by designing the Dovetail Concave (top puzzle) and Dovetail Convex (bottom puzzle), and then later on added the Dovetail T puzzle to the group (middle puzzle). As you might have guessed, the name of each puzzle corresponds to the shape of the green piece.

The term “Dovetail” is derived from the Dovetail joint, a joinery technique commonly used in woodworking and carpentry work to secure two edges together. Similar to the Dovetail joint, the green pieces have trapezoidal cross-sections (on top of their unique shapes) that fit neatly into the notches made in the aluminium block.

A diagram of a dovetail joint taken from the website technology student. The “pins” slide into the “tails” so that it becomes difficult to pull them apart.

Thus, all three Dovetail puzzles are locked firmly into place. There seems to be no way of removing the green pieces by sliding it up or down, or pulling it straight up out of the aluminium block. Cracking this puzzle will take some creative thinking. To make things even harder, the designer of this puzzle has chosen not to include solution sheets together with the product. A true challenge for all puzzlers out there (the Dovetail Puzzles come with a difficulty rating of 6/10)!

Need a hint? Think about other ways to interact with the aluminium block as a whole. The solution for all the three puzzles (Concave, Convex and T) are also very similar to each other.

Finally, some other puzzles from Wil Strijbos in our collection that you might be interested in include Aluminium Apple (just released in 2021), Aluminium Cylinder, Aluminium Cross, Dovetail Cube, Power of the Ring, and the 4-Piece Jigsaw Puzzle.

As with most of Wil’s puzzles, the engineering and craftsmanship that goes into each one of these puzzles is top-notch, and truly as impressive as the solution itself. One cannot help but appreciate the beauty and artistic design of his puzzle creations while attempting to solve them.

If you are interested in these puzzles by Wil Strijbos, and wish to get your hands on them at affordable rates, check out our Sparkbox Plans here! Also check out Project Enigma’s video on the Impossible Dovetail Puzzles and the 4-Piece Jigsaw Puzzle on Instagram and be sure to follow us for more updates :)

For those who need help solving some of Wil’s other puzzles besides the Dovetails, you can watch these helpful videos by YouTuber Chris Ramsay too:

Aluminium Cross -

Aluminium Cylinder -

4-Piece Jigsaw Puzzle -

Happy puzzling!


“Wil Strijbos.” Puzzle Score.

“Strijbos.” Logica Giochi.

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