String Cube is an inventive twist on the Void Cube that adds a whole new layer of challenge. Hand-assembled in the United States by inventor Doug Engel, each String Cube uses two strings that pass through the cube and connect to four corners, so every turn changes both the cube state and the tangle itself. The result is a puzzle that feels part twisty puzzle, part knot puzzle, and completely different from anything else in your collection.

Why you’ll like it

• Handmade in the United States by inventor Doug Engel
• A unique Void Cube mod that combines turning, tangling, and untangling in one puzzle
• Creates intricate knots and string paths as you rotate the layers
• Can be enjoyed as both a cube puzzle and a knot-solving challenge
• Removable snap-style string connections make it easy to reset and start over
• An experimental, limited-stock puzzle for collectors and curious solvers

How it works

String Cube uses a Void Cube base with two strings routed through the cube and attached to four corners. As you turn the faces, the strings wrap, cross, and tighten into new tangles. You can scramble it up and then work backward by loosening and removing the knots, or go for the full challenge by restoring both the strings and the cube.

Two puzzles in one

One of the most interesting things about String Cube is that solving one part does not automatically solve the other. You can untangle the strings without fully solving the cube, or solve the cube while the strings still need work. That gives String Cube a very different feel from a standard mod and opens up a fresh, exploratory style of solving.

Designed to stand out

The removable connector system avoids internal elastics and gives the puzzle a distinctive look and feel. The strings are designed to form smooth, lively curves, which makes the puzzle visually striking even before you begin turning. It is a conversation-starting design that looks just as interesting on display as it does in motion.

Good to know

• You can focus on the knot challenge, the cube challenge, or both
• If you get stuck, the strings can be unsnapped so you can reset
• A great pick for mod collectors, puzzle enthusiasts, and anyone looking for something genuinely different
• Limited availability