# Corn maze. **URL:** \ **Category:** Factual Questions\ **Created:** [October 17, 2011, 1:21am UTC](https://boards.straightdope.com/t/corn-maze/599868 "2011-10-17T01:21:17Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![whatsthedealman](https://avatars.discourse-cdn.com/v4/letter/w/e8c25b/32.png) [@whatsthedealman](https://boards.straightdope.com/u/whatsthedealman)\ **Post date:** [October 17, 2011, 1:21am UTC](https://boards.straightdope.com/t/corn-maze/599868/1 "2011-10-17T01:21:17Z")
Other than barging through the corn like a crazy person, is the simple solution to a maze to just follow the right or left wall all the way out if you get lost? Does it work the same way to go through the maze, start to finish? Is it possible to design a static maze that doesn’t follow that rule, if true? Is the follow-the-right-wall rule the optimal solution, the longest solution, or does it depend? Please answer, am getting cold. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [October 17, 2011, 1:25am UTC](https://boards.straightdope.com/t/corn-maze/599868/2 "2011-10-17T01:25:35Z")
Assuming that the exit is on the same wall (it can be on any side - if the maze is a rectangle) as the entrance, following the right (or left) wall always leads to the exit, although it may be a very non-optimal solution. If the exit is in the “inside” of the maze (say, an door to a tunnel), then this solution may not work. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [October 17, 2011, 1:28am UTC](https://boards.straightdope.com/t/corn-maze/599868/3 "2011-10-17T01:28:10Z")
You can build a maze where that doesn’t work. [Here’s a short article](http://www.nytimes.com/2011/10/14/science/14maze.html?_r=1&ref=science) on NYTimes about the family that called 911 when they were lost in a maze. They have some relevant quotes from a corn maze designer. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [October 17, 2011, 1:32am UTC](https://boards.straightdope.com/t/corn-maze/599868/4 "2011-10-17T01:32:55Z")
> [@beowulff](#): > > Assuming that the exit is on the same wall (it can be on any side - if the maze is a rectangle) as the entrance, following the right (or left) wall always leads to the exit, although it may be a very non-optimal solution. Of course, this approach is only guaranteed to work if you follow it from the beginning. If you realize you’re lost and _then_ start, you could just go in circles. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 17, 2011, 2:24am UTC](https://boards.straightdope.com/t/corn-maze/599868/5 "2011-10-17T02:24:50Z")
You can also make it so that doesn’t work by making the maze three-dimensional, or by making it change with time (though that would be difficult in a corn maze, unless you have some very fast-growing corn). ---
**Author:** ![Ruby](https://avatars.discourse-cdn.com/v4/letter/r/13edae/32.png) [@Ruby](https://boards.straightdope.com/u/Ruby)\ **Post date:** [October 17, 2011, 3:59am UTC](https://boards.straightdope.com/t/corn-maze/599868/6 "2011-10-17T03:59:28Z")
I’m perplexed by the family lost in the corn maze. Corn is planted in rows. Surely they could have simply walked out of the maze by following the corn row, right? ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [October 17, 2011, 4:17am UTC](https://boards.straightdope.com/t/corn-maze/599868/7 "2011-10-17T04:17:20Z")
> [@ZenBeam](#): > > Of course, this approach is only guaranteed to work if you follow it from the beginning. If you realize you’re lost and _then_ start, you could just go in circles. Relevant points to add: This is true (for a two dimensional maze) only if there are points inside the outermost borders of the maze which cannot be reached by any path from the entrance. AND If it does happen, then once one has discovered it’s happening (for example via a mark on the wall) one can simply switch to the opposite wall. A cleverly designed maze, though, could make it confusing to figure out what wall segments belong to which wall… ETA: But not if you’re allowed to make a continuous line on the wall. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 17, 2011, 4:39am UTC](https://boards.straightdope.com/t/corn-maze/599868/8 "2011-10-17T04:39:39Z")
> [@](#): > > This is true (for a two dimensional maze) only if there are points inside the outermost borders of the maze which cannot be reached by any path from the entrance. Only if you define “unreachable points” as including points on the walls themselves. You could put a “tree” of walls, without any loops, somewhere in the interior of the maze, and a would-be solver might end up just tracing around the outside of that tree. Example very simple maze: ```auto +---+ | Exit |A| | | | | | Entrance +---+ ``` If you’re at point A, facing north, when you decide you’re lost, and follow the right wall, you’ll never get out. ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [October 17, 2011, 4:46am UTC](https://boards.straightdope.com/t/corn-maze/599868/9 "2011-10-17T04:46:31Z")
> [@Chronos](#): > > Only if you define “unreachable points” as including points on the walls themselves. You could put a “tree” of walls, without any loops, somewhere in the interior of the maze, and a would-be solver might end up just tracing around the outside of that tree. > > Example very simple maze: > > ```auto > > +---+ > | Exit > |A| | > | | | > | Entrance > +---+ > > ``` > > If you’re at point A, facing north, when you decide you’re lost, and follow the right wall, you’ll never get out. I did mean it to include points on the walls themselves, but I hadn’t thought through how trivial this makes the claim. What I had in mind was the possibility of loops and single points (i.e. idealized column-like “walls”), but I failed to notice that a line all by itself (as in your graph) also constitutes a set of unreachable points. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [October 17, 2011, 11:34am UTC](https://boards.straightdope.com/t/corn-maze/599868/10 "2011-10-17T11:34:43Z")
Some corn mazes include bridges which could easily defeat this plan. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [October 17, 2011, 12:55pm UTC](https://boards.straightdope.com/t/corn-maze/599868/11 "2011-10-17T12:55:05Z")
It _doesn’t matter_ in any way shape or form if the maze is 2d/3d, has tunnels, bridges or exits on a different wall or anything. If you follow a single wall from _start to finish_ you will get out. (You may end up leaving the same entry you came in or a different one.) There are two possibilities in following a fixed strategy in a maze: either you get out or you end up looping inside. Following a wall will never loop. There is no point where the wall you are following can close in on itself and form a loop. (It is known that you can fully traverse any 2d maze using a simple strategy and two markers that you can drop and pick up. It’s very slow though. Manuel Blum, Dexter Kozen. “On the Power of the Compass (or, Why Mazes Are Easier to Search than Graphs)” _FOCS_, 1978, pp132-142.) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 17, 2011, 7:44pm UTC](https://boards.straightdope.com/t/corn-maze/599868/12 "2011-10-17T19:44:42Z")
> [@](#): > > It doesn’t matter in any way shape or form if the maze is 2d/3d, has tunnels, bridges or exits on a different wall or anything. If you follow a single wall from start to finish you will get out. (You may end up leaving the same entry you came in or a different one.) For a 3-D maze, the definition of “follow a single wall” may become ambiguous. Consider another simple maze, consisting of a single dead-end corridor with an oubliette pit at the end of it. You go down the corridor, fall in a pit, and continue to trace out the wall of the oubliette forever. Or, if you object that falling into the pit doesn’t count as “following the wall”, make it a spiral staircase that goes down into the pit. Now, if you keep following the wall, you’ll eventually end up with the wall being the side of the staircase, which dwindles down to nothingness at the floor. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [October 18, 2011, 1:29pm UTC](https://boards.straightdope.com/t/corn-maze/599868/13 "2011-10-18T13:29:05Z")
> [@Chronos](#): > > For a 3-D maze, the definition of “follow a single wall” may become ambiguous. Consider another simple maze, consisting of a single dead-end corridor with an oubliette pit at the end of it. You go down the corridor, fall in a pit, and continue to trace out the wall of the oubliette forever. Good point. I didn’t really mean 3d in the full sense. Just stuff that humans can walk thru in a standard way. A simple floor, 2 walls on either side with simple side only branches. I was thinking of bridges and tunnels type 3d-ness. No ambiguity about “the wall” allowed. In your example, “the wall” branches. One part continues on past the pit and the other goes down. ---
**Author:** ![TerpBE](https://avatars.discourse-cdn.com/v4/letter/t/bc8723/32.png) [@TerpBE](https://boards.straightdope.com/u/TerpBE)\ **Post date:** [October 18, 2011, 3:35pm UTC](https://boards.straightdope.com/t/corn-maze/599868/14 "2011-10-18T15:35:14Z")
> [@kanicbird](#): > > Some corn mazes include bridges which could easily defeat this plan. That’s correct. The corn maze near me has a bridge at the exit, so the “end” is actually towards the center of the maze, and then you go across the bridge to get out of the corn. ---
**Author:** ![Canadjun](https://avatars.discourse-cdn.com/v4/letter/c/76d3ee/32.png) [@Canadjun](https://boards.straightdope.com/u/Canadjun)\ **Post date:** [October 18, 2011, 4:01pm UTC](https://boards.straightdope.com/t/corn-maze/599868/15 "2011-10-18T16:01:08Z")
Slightly off topic question; just how tough are corn plants? My immediate thought when I read that news item about a family calling 911 was why didn’t the adults just force their way through the corn in a more or less straight line? ---
**Author:** ![Buck\_Godot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/buck_godot/32/6573_2.png) [@Buck\_Godot](https://boards.straightdope.com/u/Buck_Godot)\ **Post date:** [October 18, 2011, 4:10pm UTC](https://boards.straightdope.com/t/corn-maze/599868/16 "2011-10-18T16:10:10Z")
> [@Frylock](#): > > If it does happen, then once one has discovered it’s happening (for example via a mark on the wall) one can simply switch to the opposite wall. Not necessarily. It is possible that you are sandwiched between 2 different interior circles, in which case you would have to continue until you reach a point connected to an exterior wall. Regarding the bridges, I was imagining a bridge/tunnel that starts and ends in the middle of a room, and so not connected to any wall. A solution then is to artificially imagine that the bridge/tunnel is connected to one of the walls both before at the start and at the end, and then continue to trace your way. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [October 18, 2011, 4:31pm UTC](https://boards.straightdope.com/t/corn-maze/599868/17 "2011-10-18T16:31:08Z")
> [@TerpBE](#): > > That’s correct. The corn maze near me has a bridge at the exit, so the “end” is actually towards the center of the maze, and then you go across the bridge to get out of the corn. I am curious about this. In order to defeat the follow the wall rule, the wall has to “split” somehow. Is there a place where there is a stairs and you can opt to go straight or up the stairs, e.g., with the same wall continuing in both directions? But a slight variant still allows a simple traverse of the maze, assuming the number of such splits is small enough to remember each one and which choice you made each time. ---
**Author:** ![Terraplane](https://avatars.discourse-cdn.com/v4/letter/t/74df32/32.png) [@Terraplane](https://boards.straightdope.com/u/Terraplane)\ **Post date:** [October 18, 2011, 4:33pm UTC](https://boards.straightdope.com/t/corn-maze/599868/18 "2011-10-18T16:33:36Z")
> [@Canadjun](#): > > Slightly off topic question; just how tough are corn plants? My immediate thought when I read that news item about a family calling 911 was why didn’t the adults just force their way through the corn in a more or less straight line? Corn is very easy to push aside and walk through but some cornfields can be huge and you might have to walk for a very long time in a straight line before you hit a fence or road. Even when you get out of the field you may not know where you are, not all country roads are well marked. ---
**Author:** ![Sal\_Ammoniac](https://avatars.discourse-cdn.com/v4/letter/s/8dc957/32.png) [@Sal\_Ammoniac](https://boards.straightdope.com/u/Sal_Ammoniac)\ **Post date:** [October 19, 2011, 4:38pm UTC](https://boards.straightdope.com/t/corn-maze/599868/19 "2011-10-19T16:38:15Z")
> [@Ruby](#): > > I’m perplexed by the family lost in the corn maze. Corn is planted in rows. Surely they could have simply walked out of the maze by following the corn row, right? In a corn maze, they don’t plant the corn that way. You can push your way out, of course, but only by doing some damage to the maze itself, which is a bit uncool. Not, mind you, that it’s \*more \*cool to dial 911. But I can sympathize a little with the people who got lost. It’s surprisingly easy to do, especially if you let a seven-year-old choose which direction to go. That’s the voice of experience speaking, by the way. ---
**Author:** ![Bytegeist](https://avatars.discourse-cdn.com/v4/letter/b/9dc877/32.png) [@Bytegeist](https://boards.straightdope.com/u/Bytegeist)\ **Post date:** [October 19, 2011, 5:47pm UTC](https://boards.straightdope.com/t/corn-maze/599868/20 "2011-10-19T17:47:36Z")
> [@Sal\_Ammoniac](#): > > You can push your way out, of course, but only by doing some damage to the maze itself, which is a bit uncool. Well, I have a plan for defeating that. Poison Ivy mazes. [Next page](https://boards.straightdope.com/t/corn-maze/599868.md?page=2)