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.
203 questions
8
votes
2
answers
194
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Wrapping a cube with thick forward and backward slashes
Here are two thick forward and backward slashes, each made of two isosceles right triangles glued along the smaller sides.
For what values of n can you wrap n forward slashes and 6-n backward slashes ...
- 31.3k
5
votes
1
answer
318
views
Does this net made of congruent quadrilaterals form a closed polyhedron?
I came across a 10-year old question on math SE recently which concerns a net built out of congruent quadrilaterals. Here, the three longer sides on each face are of equal lengths, and the two ...
- 31.3k
5
votes
1
answer
214
views
Height of a corner of a partially folded sheet of paper - take 2
A previous version of this puzzle had an unintended solution which I overlooked. There was too much information and some of it was not needed to solve it. So here's another attempt and I think there ...
- 31.3k
3
votes
1
answer
216
views
Height of a corner of a partially folded sheet of paper
This puzzle has an unintended solution (see the accepted answer) that I overlooked. See the latest version that avoids this unintended answer.
A sheet of paper in the shape of a parallelogram is on ...
- 31.3k
3
votes
3
answers
270
views
She told me to pack a jacket
Control sent a strange missive, can you figure out I'm headed?
Leave your house in Durban and drive west for about an hour. There's an airfield with a jet fueled and loaded for a long flight. I know ...
- 1,639
15
votes
2
answers
351
views
Six-way pipe junction problem
You're a spaceship plumber facing a space-constrained routing problem for some pipes:
Specifically, there is a junction of size n which describes a cube that's <...
- 267
18
votes
2
answers
1k
views
Solve the "49 lines"
A big cube with 27 small cubes of 3 colors (9 green, 9 red, 9 blue).
Arrange them in order to obtain 49 good lines.
A good line is composed with only 2 colors. (not only one, not 3 differents).
49 ...
- 181
12
votes
1
answer
996
views
Turn a shark egg case into a tetrahedron
The following shape (which loosely resembles a shark egg case if you squint with your brain a bit):
... can be folded onto the surface of a regular tetrahedron in a way that covers the entire ...
- 7,553
3
votes
1
answer
138
views
Lights-out variant on an icosahedron
You have an icosahedron with a light and a switch in each face. The switch toggles four lights: the one in its face and the three in the edge-adjacent faces. A blue dot represents a light being ON. ...
- 31.3k
4
votes
1
answer
212
views
Lights-out variant on a tetrahedron
You have a tetrahedron whose faces are covered in 4 × 4 triangular grids. Each triangular cell has a light and a switch that toggles that light and the three edge-adjacent lights. The blue dots ...
- 31.3k
10
votes
2
answers
375
views
Lights-out variant on an octahedron
You have an octahedron that’s covered in a 2 × 2 triangular grid, i.e., each face is divided into four congruent equilateral triangles (cells). Each cell of the grid hosts a light and a switch that ...
- 31.3k
15
votes
1
answer
943
views
Separated but Together
Two astronauts are stranded on separate asteroids, more than a million kilometers apart. Each asteroid is a different shape: jagged, irregular, nothing alike.
Desperate for connection, they wonder: is ...
- 1,639
22
votes
2
answers
1k
views
Silhouette of a slime mold attempting to mimic a centipede
The following image depicts the little-known* Western Centipede-Mimicking Slime Mold, here seen attempting (with limited success) to take on the form and coloration of a common garden centipede:
But ...
- 7,553
13
votes
1
answer
402
views
Lights-out variant on a beveled cube
You have a beveled cube where each face is a 3 × 3 grid of square cells, each edge a 1 × 3 grid, and each corner is a triangular cell. The cells (both square and triangular) have lights on them, of ...
- 31.3k
7
votes
2
answers
619
views
Arranging squares on a cube in isometric view
The image below shows the isometric view of six unit squares in 3D space. In particular, the squares are all aligned with the coordinate axes and parallel to the coordinate planes, but we do not have ...
- 31.3k