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.
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.
There's a spot where you could just lift up the mower over the rocks to get from one side to the other. Or at least, that's how I would have done, but I have a tiny lawn and a reel mower.
I used to do it as a side wheelie for small enough rocks. Good enough, and made me feel like a pro mower when I was younger.