Mathoverflow has their "long-open problems which anyone can understand". This includes things like the integer brick problem: Is there a brick where all its dimensions (width, height, breadth, face diagonals and main diagonal) are integers? And Singmaster's conjecture: How many times can a number (other than 1) appear in Pascal's triangle?https://mathoverflow.net/questions/100265/not-especially-fam...
mikhailfranco|5 years ago
It is also nicely phrased as a class of problems, because the forest's size and shape are known to the victim, but there are no constraints on what the shape might be. Some of the classes are solved, so you can chase down the spoiler solutions, but others are still open.
https://en.wikipedia.org/wiki/Bellman%27s_lost_in_a_forest_p...
Warning: don't read these unless you want your next weekend to disappear:
http://wardsattic.com/joomla/Download/BellmanForestProblem.p...
https://www.maa.org/sites/default/files/pdf/upload_library/2...
P.S. Previously on HN:
https://news.ycombinator.com/item?id=18001449
P.P.S. I have now added PDF links to the Wikipedia article.
Ericson2314|5 years ago
ffhhj|5 years ago
If an ideal observer looks at the end of an ideal infinite cylinder, which is not deformed by perspective, when the cylinder is pointing directly in his line of sight he will see just a circle, but if the cylinder deviates slightly what will he see? A cylinder with finite length in his field of view? Or a cylinder that goes infinitely out of his field of view?
thaumasiotes|5 years ago
The only way I can think of to interpret this is that you pick a plane and project the cylinder onto it. (That's how you get the circle). But that's easy to do. Failing that, this looks like a "puzzle" that's supposed to sound interesting without actually meaning anything.
generalizations|5 years ago