Slothouber-Graatsma Puzzle | 7×7×7 Cube Packing Puzzle | Advanced Mathematical Brain Teaser | Polycube STEM Challenge

Can you build a perfect 7 × 7 × 7 cube?

The Slothouber-Graatsma Puzzle is one of the most celebrated three-dimensional packing puzzles in recreational mathematics. At first glance, the pieces appear to be simple rectangular blocks—but assembling them into a perfect cube is a remarkably challenging exercise in logic, planning, and spatial reasoning.

Originally designed by Dutch puzzle creators Jan Slothouber and William Graatsma, this puzzle has fascinated mathematicians, engineers, and puzzle enthusiasts for decades. Its elegant design hides surprising mathematical complexity beneath its simple appearance.

Our oversized editions transform this classic puzzle into an impressive centerpiece that’s just as enjoyable to display as it is to solve.

What’s Included

The complete 27-piece set consists of:

* 7 × 1 × 1 × 1 cubes
* 6 × 1 × 2 × 6 blocks
* 6 × 2 × 2 × 5 blocks
* 6 × 2 × 3 × 4 blocks

Available Sizes

Small

* Cube Size: 135 × 135 × 135 mm (5.3 × 5.3 × 5.3 in)

Medium

* Cube Size: 220 × 220 × 220 mm (8.7 × 8.7 × 8.7 in)

XLarge

* Cube Size: 305 × 305 × 305 mm (12.0 × 12.0 × 12.0 in)
* Approximate Weight: 5 kg (11.0 lb)

The Mathematics Behind the Puzzle

The Slothouber-Graatsma Puzzle is famous for its elegant construction. Although it consists of only four different block types, assembling them into a perfect cube requires careful planning and a deep understanding of three-dimensional space.

One of the puzzle’s most remarkable properties is that when the cube is completed, only one of the twenty-seven individual pieces is visible from the outside. Every other piece is completely enclosed within the finished cube—a surprising result that beautifully demonstrates the puzzle’s ingenious design.

Because of its mathematical elegance, the puzzle has become a classic example in recreational mathematics and continues to be studied and enjoyed by puzzle enthusiasts around the world.

Features

* Classic 7 × 7 × 7 cube packing puzzle
* Complete 27-piece set
* Four different block types
* One of the most famous polycube puzzles ever created
* Excellent STEM educational resource
* Encourages advanced spatial reasoning
* Impressive display piece when completed

Great For

* Puzzle collectors
* Advanced puzzle enthusiasts
* Mathematics educators
* Engineering students
* STEM classrooms
* Recreational mathematicians
* Spatial reasoning practice
* Unique gifts

Materials

Crafted from durable PLA plastic, a biodegradable and eco-friendly material designed for years of solving and display.

Difficulty

Expert

While the individual pieces appear simple, assembling the completed cube is a rewarding challenge that requires patience, experimentation, and three-dimensional thinking.

⸻

About ItemsByCL

ItemsByCL was built around one simple idea: every product should spark curiosity or put a smile on someone’s face.

We specialize in oversized mathematical puzzles that transform classic recreational mathematics into hands-on experiences. Many of our designs have inspired teachers, students, collectors, and puzzle enthusiasts around the world by making complex mathematical ideas both interactive and beautiful.

Whether you’re searching for a classroom centerpiece, an unforgettable gift, or your next great puzzle challenge, our goal is to create puzzles that are as impressive to display as they are rewarding to solve.

Thank you for supporting a small business dedicated to making mathematics bigger, bolder, and more engaging.