Questions tagged [three-dimensional]

This tag is used for geometric puzzles, if one wants to stress that the setting is not 2-dimensional but 3-dimensional.

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101
votes
1answer
7k views

How can this shape perfectly cover a cube?

The following shape: can be folded onto the surface of a cube in a way that perfectly covers the entire cube with no gaps and no overlaps. How can this be done?
101
votes
3answers
6k views

The brain-curdling eldritch horrors and the third dimension

We're in the year 2016 so it's finally time to take puzzles to the 3rd dimension! So let's see what those beautiful times bring us today: (click to enlarge) Everyone of you clever sods could as ...
54
votes
2answers
6k views

Can you perfectly wrap a cube with this blocky shape?

The following blocky shape: can be folded onto the surface of a cube in a way that perfectly covers the entire cube with no gaps and no overlaps. How can it be done?
48
votes
2answers
5k views

Six pyramids in a cube

This question is from the German mathematics competition Känguru der Mathematik. In this competition students have to solve 30 mathematical tasks like this in 90 minutes without calculator. Actually ...
46
votes
6answers
3k views

A-maze-ing Dice

This is an entry to the 12th fortnightly challenge "So you have escaped my labyrinth of words, and now you think you are free, do you? Well, I have news for you: Think again! Ha Ha Ha Ha" Having ...
36
votes
4answers
2k views

Sometimes force is the solution [RTFM]

This time we are investigating a well secured safe. Simply breaking it is not possible (I've tried). We need to find the right combination! Can you help me open it? Along with the ...
35
votes
4answers
2k views

Red Herring Bonkers In The Red Herring Bunkers

Please help me! Last weekend I hosted a hell of a party at my workplace (I'll invite you next time, promise). Of course, my boss didn't know about it. The next morning I entered the building and ...
28
votes
8answers
3k views

A hungry ant on a matchbox

A hungry ant is standing on the top of an empty matchbox cover (without its drawer) and has detected the smell of a drop of honey on the floor of the cover as shown in the figure below. What is the ...
28
votes
2answers
840 views

A simple alien safe

Oh no!! Abducted by aliens and put into a labyrinth for ability testing - again! There is (obviously) no deeper meaning behind this all, but can you help me open this safe, as it undoubtedly contains ...
27
votes
1answer
819 views

Every Fourth Wormhole

An entry in Fortnightly Topic Challenge #33: Surface Geometry Mazes
27
votes
1answer
869 views

You go wherever you go today

A conclusion to my entries in the Fortnightly Topic Challenge #32: Grid Deduction Hybrids. This metapuzzle incorporates the three previous puzzles in this series: Desert Irrigation Project I am an ...
26
votes
3answers
3k views

Stonehenge - the true purpose

During the last year I've been working on solving the mystery behind these funny stones in Wiltshire, England. Now I'd like to have you join in on the fun and hope you enjoy discovering the true ...
26
votes
1answer
1k views

A firm farewell - Rest in piece

22
votes
1answer
581 views

How can this fractal shape perfectly cover a certain platonic solid?

The following fractal shape has a surprising property: This two-dimensional shape can be folded onto the surface of a regular polyhedron (one of the five platonic solids) in a way that perfectly ...
22
votes
1answer
600 views

3D nonogram, beginner's edition

Trying out the concept of 3D nonograms. This one should be pretty simple. Name the depicted object.
20
votes
1answer
668 views

These alien safes have no end

Well, I could solve the last safe, but what did it buy me? Just another instant-teleport and boom... here I am again! In a single room with very few things around me, most notably a safe, and no ...
19
votes
4answers
2k views

Martin Gardner's “The Twiddled Bolts”

This is a puzzle of Martin Gardner, taken verbatim from My Best Mathematical and Logic Puzzles: Two identical bolts are placed together so their grooves intermesh. If you move the bolts around each ...
19
votes
3answers
540 views

Arranging cubes

You are asked to arrange 42 identical cubes such that exactly three of each cube's faces completely overlap another cube's face each. Is this task possible? If not, why not?
18
votes
6answers
1k views

Measuring Water with a Holey Cube

You have been given a transparent glass cube, which has a small hole at the center of one of the faces. How can you fill the cube with water occupying exactly one third of its volume? Edit: The ...
18
votes
2answers
2k views

Maximal-volume cube net from unit square paper

Given a square piece of paper (say 1x1), what is the largest cube net you can cut out of it? ('largest' meaning with maximal volume; 'net' meaning it's possible to fold into a cube (somehow)) This ...
15
votes
1answer
1k views

Cover a cube with four-legged walky-squares!

This is a four-legged walky-square: This shape has an interesting property: It is possible to map multiple copies of this shape onto the surface of a cube in a way that perfectly covers the entire ...
15
votes
1answer
1k views

Can you cover a cube with copies of this shape?

The following shape has an interesting property: It is possible to map multiple copies of this shape onto the surface of a cube in a way that perfectly covers the entire cube with no gaps and no ...
14
votes
2answers
650 views

3D Masyu - A Die

Fold this net into a cube and solve this 3D Masyu. The original Masyu rules apply. In addition, question mark '?' should be replaced by either a black or white circle. Side note: Yeah, it's almost ...
14
votes
1answer
879 views

3D nonogram – Name the object

This is a 3D nonogram. The first five boxes represent the five layers of a $5\times5\times5$ cube, and the last box shows the enumerations for the Z-axis. (Note that 11 means two stretches of length ...
14
votes
2answers
793 views

Flood on the top floor

There has been a water incident on the top floor of a building, and one apartment has suffered some water damage. As in, a lot of water damage. The entire apartment is filled waist deep with ...
13
votes
7answers
3k views

Fair n-sided dice

I have recently bought a fair $10$-sided dice for generating equally distributed random numbers from the range $1,2,\ldots,10$. Let me describe this dice in some more detail. Consider a regular 5-gon $...
13
votes
4answers
602 views

Color the cubes, then assemble them to form a larger cube

Goal: Paint 27 cubes using three colors (for example, red, yellow, and blue), so that you can form a 3x3x3 cube with all surfaces in red (for example), a 3x3x3 cube all in yellow, and a 3x3x3 cube all ...
13
votes
2answers
422 views

A cubeful of three-dimensional devilry

This is a three-dimensional cryptic crossword. The seven squares represent the layers of a $7\times7\times7$ cube. The clues are a mix of Printer's Devilry and normal cryptic clues. Across 13. ...
12
votes
3answers
669 views

3D Crossword, Cryptic, Statue View & Maze

The following image depicts the layers of a $5\times5\times5$ cube. Using 3-dimensional thinking, can you find the way out of the cube? Empty version with no crossword numbers Empty version ...
12
votes
1answer
644 views

Reverse dots and… cubes? - Snowflake edition

A Reverse dots-and-boxes puzzle inspired by @jafe Albert and Robinson are playing a game of reverse dots and boxes. The players take turns adding one plane in one free spot on the grid (...
11
votes
2answers
971 views

Wooden Snake Puzzle

I have a wooden snake puzzle in my collection that has been unsolved for years. I wondered if any of you might be interested. I have fiddled with it, but think it might need dynamic programming or ...
11
votes
1answer
674 views

Three-dimensional light bulbs

This is a three-dimensional Akari puzzle (also known as Light Up). The six squares represent the layers of a $6\times6\times6$ cube, top to bottom. The objective is to add light bulbs into any number ...
11
votes
1answer
235 views

Brain-breaking 3D masyu

This is a three-dimensional masyu puzzle.1 The five squares depict the layers of a $5\times5\times5$ cube. The goal is to make a single loop in 3D space which fulfills the following properties: The ...
11
votes
1answer
173 views

Rhombicosidodecahedron Slitherlink

This is a Slitherlink puzzle, being played on the surface of a 3D object, a Rhombicosidodecahedron. If you are not familiar with Slitherlink puzzles, I don't suggest starting on this one. Rules in ...
11
votes
1answer
165 views

3D devilry, DIY edition

This is a diagramless three-dimensional cryptic crossword. Solve the clues and then fit the answers into a three-dimensional grid. The numbering of the clues starts from the #1 (nearest) layer. On ...
10
votes
2answers
738 views

Polygon wrapping a cube

A polygon is folded to perfectly wrap a cube, covering all of its surface area with no overlap. Show that the polygon had at least two equal angles.
10
votes
1answer
307 views

3D nonogram – What's in the box?

This is a three-dimensional nonogram. The first six squares depict the layers of a $6\times6\times6$ cube. The final square gives the enumerations for the Z-axis, top to bottom. Some rules: The grid ...
10
votes
1answer
476 views

3D nonogram – What's going on?

This is a three-dimensional nonogram. The first six squares depict the layers of a $6\times6\times6$ cube. The final square gives the enumerations for the Z-axis, top to bottom. Some rules: The grid ...
10
votes
1answer
280 views

Volcanic 3D masyu

This is a three-dimensional masyu puzzle. The six squares depict the layers of a $6\times6\times6$ cube. The goal is to make a single loop in 3D space which fulfills the following properties: The ...
10
votes
1answer
158 views

Pure 3D Crossword

This puzzle was made as requested by EKons, here. So, enjoy this three-dimensional realistic sensation!
10
votes
1answer
302 views

Is this 3d Sudoku possible?

I was looking at images of 3d Sudoku's on Bing, because I was looking for a $9\times9\times9$ Sudoku, where each horizontal, vertical left-right and vertical top-bottom plane was also a Sudoku. ...
10
votes
2answers
685 views

Various cross-sections of platonic solids

We're going to take the 5 platonic solids (tetrahedron, cube, octahedron, dodecahedron, and icosahedron) and suspend them in various ways (we'll assume that they are solid and of uniform density). ...
9
votes
2answers
1k views

Create a cube from identical 3D objects

The diagram is the outline of the surface of a 3D object. Several objects, like the one created from this given surface, may be used to create a cube. Let me know if you need more clarifications to ...
9
votes
2answers
606 views

Yajilin minicubes: the Hullabaloo, the Brouhaha, the Bangarang

These are three-dimensional yajilin puzzles. In each puzzle, the four squares depict the layers of a $4\times4\times4$ cube. Shade some cells on each layer. The numbered cells show how many ...
9
votes
1answer
203 views

A Difficult Rhombicosidodecahedron Slitherlink

This is the evil older brother of this puzzle. I'm posting it more out of scientific curiosity than because it is a fun puzzle, because it is not a fun puzzle. It's just really hard. I wrote a ...
9
votes
1answer
366 views

How many cubes are crossed by a diagonal?

A cuboid is composed by $81 \times 125 \times 128 $ cubes. How many cubes are crossed by a (main) diagonal of the cuboid? (note: I chose the numbers for the sides so that the case of the diagonal ...
9
votes
2answers
341 views

A cube with colors

There's a word encrypted in this mysterious cube. Can you find out what it says? (See end of post for 3D model) >>SPOILER: Now that the puzzle has been solved you may have this 3D model<<
9
votes
3answers
1k views

Need help solving 3d wooden cross puzzle

I'm trying to solve this puzzle and need some help with the solution: These are the pieces: The size is: 60mm x 40mm x 10mm. Any help appreciated. How do you solve this?
9
votes
1answer
352 views

So long, and thanks for all the fish?

...
8
votes
6answers
877 views

Inside Out and Back to Front

Here's a quickie: I own a shirt that has a logo on the chest on my left side. This morning I accidentally put it on inside out and back to front. Where did the logo go? Please explain your answer ...