Coffin's Quartet - Interlocking puzzle by Stewart Coffin (STC #93)

thingiverse

## ## Coffin's Quartet ### Interlocking puzzle by Stewart Coffin (STC #93) Assemble the four pieces into a 3x3x3 cube. This is a neat little design that makes a great introduction to Stewart Coffin's interlocking puzzles. As a puzzle, it's not too difficult, but it's a very elegant design: a 3x3x3 cube dissection that completely interlocks. Coffin wrote of this puzzle: "[D]issections of the 3x3x3 cube continue to fascinate me, but especially those that interlock. Better still, with all dissimilar non-symmetrical pieces. Is such a five-piece version possible? I doubt it, after having searched for years. ... A four-piece version that satisfies all of these requirements can also be entertaining. Here is one." Coffin also poses a provocative question: "How many others are possible? Why not explore on your own ..." If you like this puzzle, you might try searching for other similar designs ... and please post any that you find! This puzzle has gone by various names over the years, including _Interlock Four_, _Coffin's Quartet_, and _Coffin's Four-Piece Cube_. Coffin's own "official" name is _Four-Piece Serially Interlocking Cube_. I usually prefer the canonical names, but that's a mouthful, so in this case I went with perhaps the most widely used of the others. UPDATED February 2020 with a new design and larger pieces. ### Printing Instructions Print either `coffin.coffins-quartet.stl` _or_ `coffin.coffins-quartet-smaller.stl`. I prefer the larger version, but the smaller one will use around 1/3 less material. After you print it, first connect all the joints before attempting to solve the puzzle. Snap each male connector into a corresponding female connector (for example, the male connector labeled "A" should connect to the female connector with a matching "A" label on the interior). The joints are designed to be tight, and depending on the printer and filament used, you may need to hammer them into place. If they come out too loose, a drop of superglue will make them more solid (in most cases this shouldn't be necessary, but unfortunately tolerances vary across printers and filaments). The snap joint concept is discussed further in this blog post: [Adventures in 3D Puzzle Printing](https://normalplay.blogspot.com/2019/01/adventures-in-3d-puzzle-printing.html). The puzzle is modeled using [puzzlecad](https://www.thingiverse.com/thing:3198014), and I have included the .scad file in case you want to remix it. ### About the Designer Stewart Coffin is perhaps the most influential designer of interlocking mechanical puzzles, having produced a wide range of ingenious designs of various shapes and complexity. More information on Coffin, and a variety of other printable models of his designs, are available in the [Stewart Coffin Puzzles](https://www.thingiverse.com/asiegel/collections/stewart-coffin-puzzles) collection. Happy puzzling!