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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.

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.

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.

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.

A lawn mower cuts grass whether you push it forward or pull it backwards: my trick when I was a kid was just to push and pull it back and forth across the lawn without changing the direction it faced at all.

it's Q*bert!

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.

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.

> 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.

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.

Reminds me of Zachtronics: Take a computationally difficult problem, reduce it to a game, and then score people against each other.

Pure genius and nerd snipe marksmanship.

Did you know multi-robot exploration pretty much as laid out in Exapunks has loose but well studied bounds on number of agents, bits of information, and exploration steps?

For example, one agent with only one pebble cannot explore all graphs?

https://josh.vanderhook.info/media/pdf/exapunks-graph.pdf

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!

Seems like the most optimal path would also account for returning the mower to its storage space...

Fun article, but this didn't actually answer the "why" question for me...

Hear me out: It's a low flying drone with a propeller on the undercarriage as well which is used to cut the grass. Voilá, no wheel lines.

This is a pretty big deal once you scale it up.

https://link.springer.com/article/10.1007/s11119-023-10033-9

That reminded me a lot more of Chip's Challenge than of mowing a lawn. Just missing some blocks to push!

The author's objective function is incorrect, negating the core claim.

Better is subjective here i think, what about laying some nice stripes or diamonds? How do you work in some aesthetics and still stay efficient?

I'm sure I'm the odd ball, but ever since I was a kid, I liked the diagonal patterns much more than the square lines.. and I'm not just talking about lawns. I would vacuum my room on diagonals.. lol

have to say i really enjoyed how this was presented.

no comment on the results or the premise of are people good at mowing or just good at playing "snake"

i would be very curious to see if this same result held up when you also factor things like turn effort or "prioritize the longest straight lines bc they look cool"

When I mow lawns I teleport forward 6ft at a time and then a 6x6 square of grass vanishes beneath me.

In the nude.

Mowing the lawn is never about mowing but people wanted to be busy, feel productive for a bit, some exercise, and helping to clear thoughts. For others it might be driving long roads, or doing chores inside the house, cycling, and such. Otherwise, it’s inefficient and useless, the lawn can be replaced with better flowers or even small garden, or simply pave it and save the time and efforts and electricity/water doing a repetitive thing like it, and also spare your neighbors the noise 7am Saturday morning, and if you look at the bigger picture, the process is a total waste, you waste water to grow crops only to waste electricity to mow it later, it provides no useful product or outcome either, no flowers, no food, not even cosmetics like fancy looking garden, plus the maintenance and/or initial installations.

It makes like 30 turns as the "best", but if the program ever used a mower, it would want to minimize turns.

Probably the same reason some food delivery people place my bag next to the door instead of in front of the outward opening door where it will tip over, unsure what that reason is but I’d like to know.

The optimum path does not take into account row striping :)

100 percent first try. Too easy.

I hate this game.

Mowing a lawn is about creating straight even lines not optimal routes.

Dig that lawn out and start growing food, ffs.

the article kinda ignores that the direction of mowing matters, optimal path would look shit

> You’ve probably done something like mow a lawn or vacuum a rug hundreds of times without thinking much about it. Some part of your brain works out a route that’s usually good enough to get the job done. People are actually pretty good at this, and better than you’d guess for a problem that is hard for computers. We wanted to see it for ourselves, so we built a lawn and asked people to mow it.

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