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.
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Join six five-link chains to form a circular chain
Join six five-link chains to form a circular chain.
To join two chains, you must cut, and then re-weld, a link.
The final number of links in the circular chain will be 30.
What is the minimum ...
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Connect the colored dots
I've got this:
By connecting the dots, I get this:
Could you do the same for this one:
There is a unique solution.
The rules are: You have to use every square, lines can't cross each other and you ...
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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 ...
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Ernie and the Underground Network
I haven't seen Ernie for a few weeks - he's been on holiday in the People's Republic of Kzijekistan (PRK). But yesterday I got an e-mail and thought I would share it with you. It reads as follows:
...
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Number of ways to fold a 2x4 map
M.Gardner in his book "Mathematical puzzles and diversions" states that the following 2x4 map
$$
\begin{array}{|c|c|}
\hline
1 & \phantom{1} & \phantom{1} & \phantom{1} \\
\hline
\...
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How to generalise hang picture puzzle?
There is well known problem:
The picture is attached to a string and you want to hang it on N nails so that if one takes out any of the nails, the picture falls. How do you do it?
For those who ...
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Is there a proof that a map of the United States requires 4 colors?
The Four color theorem states that no more than four colors are required for any map. Can it be proved or disproved that 3 colors can be used for United States map?
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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 ...
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