Not an off-by-one error—at
least not in spirit. Interesting nonetheless.<p>I expected the article to eventually answer this puzzle:<p>> The competition started and got through a number of rounds. There were some comments about how the climber on the left always won.<p>Near the end:<p>> The kicker is that the out of place hold hasn’t been used in a long time. The climbers have optimised their route such that it is skipped. The same happens to the fourth hold from the bottom. So either being in the wrong place is immaterial to the climbers’ technique as long as they don’t get in the way.<p>So it seems like the error discovered by the article author should not have conferred any advantage to the climber on the left.<p>Anyone who can shine light on this matter?
In terms of real-life off-by-one errors, it's hard to beat the town of Wemding in Bavaria (Germany).<p>Here a pyramid of 120 blocks is planned, with one placed every ten years. It started on the 1200th anniversary of the town, and is planned to be complete 1200 years later... and I'm sure you've spotted the problem.<p>Matt Parker, the 'stand-up Mathematician' has a video on it: <a href="https://youtu.be/FAdmpAZTH_M?si=_u8fM-fprUWiEqZ9" rel="nofollow">https://youtu.be/FAdmpAZTH_M?si=_u8fM-fprUWiEqZ9</a>
If you cross your eyes and look at the routes as if it were a single stereoscopic image overlaying one route on top of each other, the misplaced hold jumps out at you immediately.
Great find!<p>One comment on what the article says:<p>> If this were actual code review the correct comment would be something like “this [piece] hasn’t been used for years, it should be deleted”. But this is something in physical space, and there would be arguments that removing it (them) means the route has changed, thus times are no longer comparable.<p>Hmm, I think the correct analogy is rather a benchmark. Like code in a benchmarking tool or test, the whole climbing course does not serve any purpose, any actual goal, except to be completed as fast as possible.<p>You wouldn't say "these instructions should be deleted because branch prediction and speculative execution in recent years have made it so that total cycle count is the same without them", for the reason stated ultimately after in the article already: That may not have been true in the past, and may change again in the future.
That's funny.<p>I discovered an off-by-one error in college as I was graduating. Apparently the "class plan" I had put together with an advisor during my second year was missing a class, and I discovered it as I petitioned it for graduation. "You're one class short."<p>(It was for my second major, not the primary one, and the head of the physics department was nice enough to credit a nonlinear optimization course from engineering toward the major, so I earned it.)
This week in 1945, an off-by-one error disrupts the surrender ceremony ending World War II: <a href="https://www.theglobeandmail.com/news/world/how-a-canadians-mistake-70-years-ago-almost-botched-japans-surrender-document/article26201436/" rel="nofollow">https://www.theglobeandmail.com/news/world/how-a-canadians-m...</a>
That's a fantastic find. I imagine some standard CV tool can spot this since the holds are grid-aligned. We should probably have something like that. It's crazy how good human pattern-recognition can get when trained on things. What a spot by you.<p>Also, by the way, where is the photo on your about page: <a href="https://images.squarespace-cdn.com/content/v1/60f40aa1942bba66cf802d7d/14cdc61e-d4b4-4e51-9a37-1698bcda4491/avatar_2024.jpg?format=2500w" rel="nofollow">https://images.squarespace-cdn.com/content/v1/60f40aa1942bba...</a><p>I feel like it's Crater Lake, Oregon, but considering where you live it's probably somewhere in Switzerland. Looks lovely.
> Maybe when the record is unbeaten for more than a couple of years they should throw it all away and start with a brand new route?<p>There's been some discussion of having new speed routes every few years. I think this would make the event a thousand times more interesting. That said, I'm still not sure I'd be interested.
Seems bizarre to keep the same wall config for all of time. The sport becomes about muscle memory more than anything else. The competitors can literally turn off their conscious brain. It would seem to me, it would be more exciting as a spectator and competitor if they had to problem solve on their way up there. Records could be less about best times and more about how many rounds did someone win in a row or something.<p>They could even still incorporate the one standardized wall config as a speed round once in a while or integrate it into the competition in some other way.
> Also, maybe in future someone will optimise the route using that currently unused hold four down from the top?<p>This reminds me a lot of how Brood War meta changes as new 'bugs' are discovered, since the fandom loves the game without it ever being touched so when edge cases are discovered they become part of the game rather than something to be fixed.
Little known trivia: the code that won the RSA rc5 56bit challange had an off by 1 error.<p><a href="https://archive.nytimes.com/www.nytimes.com/library/cyber/week/102497computing.html" rel="nofollow">https://archive.nytimes.com/www.nytimes.com/library/cyber/we...</a>
My favorite off by one error is that the index of a count down is always one less than the amount that you subtracted. This means if you count up and down at the same time, you won’t count the middle number twice.<p>1: 1, 10 :0<p>2: 2, 9 :-1<p>3: 3, 8 :-2<p>4: 4, 7 :-3<p>5: 5, 6 :-4<p>Since the sum on each line is 11, the sum of all the numbers from one to ten is 55.<p>The cool thing is that this generalizes<p>1: 1, N : 0<p>2: 2, N - 1 :-1<p>3: 3, N - 2 :-2 <-sum is N+1<p>…<p>N/2: N/2, N -(N/2)+1 => N/2+1<p>So the sum of N numbers is N/2 * (N/2+N/2+1) => N/2 * (N+1) if N is even.<p>It appears to be broken for odd numbers<p>1: 1, 9 :0<p>2: 2, 8 :-1<p>3: 3, 7 :-2<p>4: 4, 6 :-3<p>5: 5, 0 :-4 <- can’t reuse 5<p>But for odds, setting the odd number K equal to N+1, N is an even number so the total sum is sum(N) + N+1. We showed that sum(N) = N/2 *(N+1). So we have N/2 * (N+1) + (N+1).<p>But that means N/2+1 * (N+1) equals sum(K)<p>=> (N+2)/2 * (N+1)<p>=> (K+1)/2 * K<p>So the formula N/2 * (N+1) computes the sum of N numbers if N is odd too! It works for all numbers. Wow!<p>[Edit: Formatting]
You wouldn't want to remove unused holds, because in the future, someone may find a more efficient path the makes use of that hold, but ignores other ones.
>The kicker is that the out of place hold hasn’t been used in a long time.<p>I’m guessing the belay rope issue was real and the actual cause of the other lane always winning then.
An AI image prompt could easily detect the misplace grip, but there's probably no other sport that needs to detect exact placements of things is there?