[trott]

They started with N >= 120x3 tasks, and gave each task to 4-9 humans. Then they kept only those 120x3 tasks that at least 2 humans had solved.

[tananaev]

That's a very small sample size by task. I wonder if they give the whole data set to an average human, what the result would be. I tried some simple tasks and they are doable, but I couldn't figure out the hard ones.