Pieces-of-Eight – Assembly puzzle by Stewart Coffin (STC #77)

Pieces-of-Eight

Assembly puzzle by Stewart Coffin (STC #77)

Assemble the eight pieces to form a 2x2x2 cube or one of several other shapes. This is a fun and creative design whose pieces are based on an unusual dissection of the cube. Coffin wrote of this puzzle:

“The eight dissimilar pieces of Pieces-of-Eight plug into each other to construct a cube and many other shapes. One need not be a puzzle expert to enjoy this one. The pieces are fun to just play around with, and I thought they might have educational potential as well.”

An optional tray is included (per Coffin’s specifications) that can hold all the pieces in a flat 1x3x3 configuration, as shown in the cover photo. If you choose to print the tray, you may also print the two extra half-pieces, making an expanded set that fully packs the 1x3x3 tray. Fitting them all in the tray is a puzzle in itself! You might enjoy experimenting to find other shapes that are constructible with the expanded set.

This puzzle is notoriously difficult to make in wood. Eric Fuller, the renowned puzzle craftsman, wrote: “When I first started collecting, I was not a woodworker and had no way to make myself a copy. I never could find a copy of the ‘Pieces of Eight’ puzzle for sale, and now I know why. It’s really difficult and time consuming to make. … I am never making these again!”

It’s not quite a walk in the park to print, either, but it’s a lot easier than crafting one out of wood. Hopefully this model will enable anyone with a 3D printer to enjoy a serviceable copy!

Printing Instructions

Print one copy of coffin.pieces-of-eight.pieces.stl. Optionally, also print one copy each of coffin.pieces-of-eight.tray.stl and coffin.pieces-of-eight.extra-half-pieces.stl.

The unusual shape of the pieces makes them moderately challenging to print. I obtained best results by printing them directly as oriented in the STL files, with the following settings:

• Brim
• Supports on build plate only
• Support angle less than 45 degrees (supports are required to span a roughly 1 mm gap along the base of a few of the pieces, but shouldn’t be needed for the self-supporting 45-degree up-slopes).

It is possible to rotate some of the pieces so that they stand upright and are printable without supports or a brim. On my printer, however (Prusa i3 MK3), I obtained better results in the given orientations, which mostly avoid “downward-facing” half-cubes.

The Printable Puzzle Project

The Printable Puzzle Project aims to make available high-quality open-source models of many puzzle designs. All of our models are posted with the generous permission of their designers and are licensed for non-commercial use only. Anyone may print copies for their own personal use, but selling or otherwise monetizing them is not permitted, and puzzle designers retain all rights as copyright holders of their work.

Our puzzles are modeled using the open-source puzzlecad library. The .scad file is included with this model in case you want to modify any of its design parameters; more information on how to do this can be found in the PPP Puzzle Modeling tutorial.

About the Designer

Stewart Coffin has been called “the most outstanding designer and maker of interlocking puzzles that the world has ever seen”. He is credited with over four hundred designs, has pioneered numerous ingenious puzzle forms, and has written extensively about puzzle design and craftsmanship. More information on Coffin, along with many other printable models of his designs, can be found on the Stewart Coffin Puzzles overview page.

Happy puzzling!