Questions tagged [topology]

A puzzle about disentangling knots, folding paper, separating strings and wires, and understanding the connectivity properties of elastic figures. General topology questions are off-topic but can be asked on Mathematics Stack Exchange.

Topology is a branch of mathematics that is sometimes also called "rubber-sheet geometry". Topology studies those properties of geometric figures that remain unchanged under distortions and deformations (like twisting, shrinking, and stretching), as long as no surfaces are torn or cut.

Typical topological puzzles are:

  • Wire puzzles: two or more entangled pieces of more or less stiff wire. The closed pieces might be simple rings or have more complex shapes. Normally the puzzle must be solved by disentangling the two pieces without bending or cutting the wires.
  • Wire-and-string puzzles: where a ribbon or piece of string is added to a wire puzzle

General topology questions are off-topic but can be asked on Mathematics Stack Exchange.

37 questions
30
votes
4 answers

Smallest Unicode Box Drawing

What is the smallest box diagram you can draw which uses all of the Unicode box drawing characters at least once, but without leaving any loose ends? For reference, you must use each of these characters at least once (not counting the spaces, which…
Darrel Hoffman
  • 4,499
  • 17
  • 32
18
votes
6 answers

Turning My Pants Inside-Out

A 12-foot long rope has two ends. One end of the rope is tied around a man's left ankle and the other end is tied around the man's right ankle. If you are not allowed to untie the rope and you're not allowed to cut the rope or change the rope in…
NL628
  • 7,490
  • 3
  • 34
  • 77
18
votes
11 answers

IQ Test Example

I'm reading up on various IQ tests, and a slideshow that I stumbled upon gave the following example: This doesn't make sense to me, as none of the options duplicate the conditions in the far left image, and it's left me thinking that it's simply a…
Callum Bradbury
  • 961
  • 5
  • 15
3
votes
2 answers

Are there any topology puzzles similar to The Seven Bridges of Königsberg?

Leonhard Euler proved that it is impossible to solve this puzzle: The challenge is to take a walk around the area depicted, and cross each bridge (yellow) exactly once. Using topology, Euler proved that it is impossible to walk each bridge exactly…
TheDoctor
  • 647
  • 5
  • 15
3
votes
1 answer

Topology puzzle: Glueing the edges of a square to itself

It is well known that if you start with a two-dimensional square and could glue — in the most straightforward way — the top and bottom edges to each other, and likewise the left and right edges to each other, then the resulting surface is a…
user76726
2
votes
2 answers

Some puzzles just appear while doing diy

I had fitted a camera above the built-in wardrobe in our children's room. There was a socket behind the drawers. I could just remove the drawer to plug it in, but there was only enough room to slide the wire up the six inches or so behind the next…
Colin Ellis
  • 123
  • 3
0
votes
4 answers

Is the following topology puzzle impossible to solve?

There was a problem I was introduced to in grade school which my teacher claimed that not even his graduate level students could solve, and it went a little like this. You have a set of boxes in a brick-like pattern which looks like so: your…
tuskiomi
  • 552
  • 2
  • 13
0
votes
1 answer

Remove foldback clips from closed loop string

This is not a trick question. In my hands, I have a closed loop string with two foldback clips: Is it possible, and if so, how can I remove one or both foldback clips from the closed loop string without cutting the red string with scissors nor…
-1
votes
2 answers

Ant-Man in chains

"Ant-Man" is a superhero that can change his size. Usually he can get very small, but sometimes he can get large as well. In the movie 'Ant-Man' (minor spoiler here) there is a scene where he is handcuffed. He manages to get small and thus slip…
Jiminion
  • 1,952
  • 14
  • 19