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- Hacker News
- > Sarah, an avid gamer, seemed to recognize this strategy immediately.
As soon as I read this, I immediately thought of the puzzle in the last gym of the Gen 3 Pokémon games (Ruby/Sapphire/Emerald). It was a big ice platform that cracked after stepping on it once, and backtracking meant falling through the ice and having to start all over again.
by crylo - It made me think of the “step on all the colored tiles without crossing your path” puzzles in Links Awakening!
I wonder how the optimal path changes if turns are penalized as well as steps - in real life turning a lawnmower takes a lot more effort than moving the same spot twice in a straight line.
- Seems like the most optimal path would also account for returning the mower to its storage space...by _philipalan
- I had a neighbour once who was quite unhappy about how short their lawnmower cut the grass, I did show them the two adjustment screws to raise the ground clearance...by TomK32
- In addition to the obvious things already mentioned, the authors miss a subtle but important point. Regardless of one’s preferences for efficiency, turning, patterns, grooves, etc.. once you are done mowing the lawn you don’t just leave the mower in the yard and go to sleep. Their ‘perfect’ solutions take 11 steps longer than finishing on the right.by ijjtpt
- WJW. This entire article is assuming there’s a single measure of “success” in this endeavor and the simulation isn’t remotely anything like mowing an actual lawn.
I’m usually a huge fan of Pudding, but this completely misses the mark.
by calmbonsai - Though I solved it in 49 moves (yay me), I realized when thinking about efficiency, it didn't take into consideration two important things: 1) all of the turns I was making in order to be most efficient, whereas overlapping a few times would have probably taken less time, and 2) I spent a lot of thinking on the spot, as to what was the most efficient path, rather than moving the mower.. so while I only took 49 moves, the time spent on inaction may have balanced the scales with someone who just kept moving.
There's a life lesson in there somewhere, I'm sure!
by tsizz - This is a really nice presentation of how some people play the authors' lawn-moving game better than others -- a great analysis of the gameplay. But the majority of comments on this HN thread right now are reacting to the title rather than to the article, as if it were about real-life lawn-moving.by svat
- And not enough people are reacting to the rocks that should just be removed in the first place to make the optimised algorithm a lot simpler. And I thought I was on HN.by sunrunner
- There are a number of bad premises in this article.
For example, most people in the world (outside the USA in particular) have never mowed a lawn. I live in a city of 3.5 million and essentially no one has a lawn.
When you really mow a lawn terrain matters. Most lawns are not flat. One goes on lines of equal height not up and down a hill.
Edges are different than the interior part of the lawn, particularly if they abut flower beds, curbs, etc.
Re passing a given spot is sometimes an efficient way to mow it properly. Particularly in dead ends and odd corners. Etc.
by contubernio - Lawns are absurdly common in South American homes, at least on the more affluent areas of the cities.
The difference is that usually homes in latin america have big fences and gates at front, so lawns are private spaces, and not the private as property but not in the privacy sense as in America.
by elzbardico - I have a small yard and I'm not optimizing for the fewest moves, I'm optimizing for both the longest continuous lines (because I think they look nicest) and the shortest distance to carry the clippings at the end.
I have a different definition of optimal to this game.
by adregan - I always mow a different path each time because turns and wheels slowly build up damage to the lawn and so I want to spread that out over everything. Push mowers are light enough that this doesn't matter but a rider it does.by bluGill
- Conversely, I once had a very large yard for a suburban home, about a third of an acre. I sectioned my yard into about 5 sections, but I mowed pretty much the same way: whatever lines are longest without stopping.
The less time I spent in Alabama heat, the better.
- I optimize for the longest continuous lines because it takes less time and effort to mow in that way.by pmontra
- Or be like me and just mulch the clippings
(yes it looks uglier that way - and yes I think of mowing the lawn as a chore)
by jannyfer - I'm right with you. My dad was a farmer and taught me: First deal with the irregular, annoying parts on the outside. Create rectangles with a long side and turning space on each shorter side. Then deal with each rectangle by going back and forth along the long edge. The turnarounds are also a great place for some wheelbarrows to collect the clippings closest to the Komposthaufen.
Hence why I went for the irregular strange part on the lower left first, and then the more regular part on the right. That's the weird rain collection, herb garden, thing we have at the back.
by tetha - Yeah, I think most people who have a yard wouldn't have played it for fewest moves... I don't know why but this whole piece reminds me of someone that never had to mow their yard, or AI that optimizes for something without carrying the full context or nuance of why we might not have gone with fewest moves optimization.by psygn89
- I started doing it and immediately felt like I was optimizing for minimal moves like a video game, rather than what I'd actually do which is not the same strategy. There's a handful of things different
- The direction you mow leaves a pattern that I generally try to stay parallel to, and mow alongside, and go for long strips even if I have to do a bit of running over already-mowed parts
- I may go diagonal at times
- I've never had a yard that's a maze of rocks
- If there's a small patch I need to mow around, like a garden, I'll likely do a circle around that and use the edge of that mow line as a new edge
I'd bet the vast majority of people who did the game input a series of moves that doesn't reflect that closely to what they'd do in real life.
by hbn - It wasn't even clear how they were going to score it, or if it was said then I didn't see it.
I kinda guessed they would score it the way they did - the number of squares you traveled through, but at the same time I was half aware of doing what I would do in real life which is to minimize the number of direction changes, not distance traveled.
- Yeah not realistic until:
* You need to pick up dog poo, dog toys, kids toys and clothes pegs
* You need to move the trampoline and mow that part and put it back.
* Some of the grass is so thick you need to whipersnap it first.
by hahahaa - Semi-related: Worked as a landscaper during my youth, one of my first jobs
I used to think that the line patterns mowed into grass were a purely aesthetic thing.
It turns out, the lines are mowed in a rotation to prevent wearing out the grass and causing damage. First you mow length-wise, then width-wise, then diagonally, finally diagonally in the opposite direction, before cycling through again.
Useless information for you today.
by gavinray - wat. Causing damage to the grass you're hitting with a (relatively) blunt object in the first place? All you did was waste three times the gas.
- What if your yard is only crabgrass
- How often did you mow the same grass to have to care about the direction of the previous mow?
I mow my garden between one to two weeks, according to the time of the year and sometimes I stop in June, if it stops raining like in 2022 and this year.
by pmontra - I don't usually do the diagonal paths but I do try to go at right angles to the previous mowing each time I mow the lawn (excepting when I can't remember which way I did it last time, but it's usually still visible) or a few narrow areas which really only make sense to mow in one direction.by SoftTalker
- Surprised no one here just does the outside border and spirals in (pinching off and immediately finishing irregular bulges). Looks neat, though more organic than rows, and is naturally motivating, as the second "half" always seems to go much quicker. Spiral the other way next time for evenness.
- You worked for someone better than average, or I worked for someone worse than average, because this sounds like a thoughtful touch and they never told us anything like that.
- Absolutely correct. If you always mow in the same direction, the grass always gets pushed in the same way by the lawnmowers blades and it will eventually morph to that direction and lose strength, which appears as grass that doesn't stand straight up, and it looks worse.by deweywsu
- This is a very different problem than actual efficiency when mowing a lawn or vacuuming a rub. Turning takes more work and time, and you miss a part of the 'square' when you are turning (the arc of the curve is not a straight line). In addition, vacuums especially have an area at the edge of the machine that is not cleaned as well, which is why you want a bit of overlap in your lines.
Plus, when mowing a lawn, you often want to leave a nice pattern, so you cant just go for pure efficiency.
by cortesoft