[Jach]

It's not very useless. The title suggests a perpetual motion machine, so I was wondering what that was doing on HN. Knowing you have to lift it first (from the article or from the comments) is important to know and lets one think this isn't necessarily made up.

[mmanfrin]

You infer a perpetual motion machine, they say it is 'powered by gravity'.

[mayanksinghal]

Which is something I infered as well, and probably many others. The title is confusing and that is all the OP was pointing at, so you know, be nice - he wasn't trying to undermine the achievements, if any.

[bmelton]

If you had an infinitely long rope and access to an infinitely deep chasm, then there's no reason it wouldn't be considered a perpetual motion machine.

[kevinh]

With an infinitely long rope and an infinitely deep chasm there would not be substantial gravity pulling it downward to have perpetual motion.

[rtkwe]

No gravity would simply approach infinity as you descended the well. And since we're being pedantic that's not an issue.