Nicky Case built the thing everyone else would have founded a company on, then waived the copyright so anyone could take it

Parable of the Polygons takes about six minutes. You drag little squares and triangles around a grid. Each shape is mildly, reasonably biased: it just wants a third of its neighbours to look like it. Nothing more. You run it. The grid segregates, completely, every time.

That is a result from Thomas Schelling's work in the 1970s and it wins a Nobel Prize in economics and almost nobody outside the field ever internalised it, because reading it does not do what dragging it does. Nicky Case and Vi Hart made it draggable, and now it gets taught in schools, cited in papers and sent around every time somebody argues that individual intentions are what matter. The idea got out of the journal because someone made it playable.

Forty-two of them, all given away

There are forty-two projects on the site. The Evolution of Trust, which teaches game theory by making you play it. We Become What We Behold, a minute-long game about how media coverage manufactures the conflict it reports. Adventures with Anxiety, in which you play the anxiety. Coming Out Simulator, which is autobiographical, and which is a harder thing to make than anything else on this list.

Every single one is in the public domain. Not open source with conditions, not free-with-attribution: a copyright waiver, so anyone can take it, change it, translate it, put it in a textbook or sell it, without asking. Parable of the Polygons alone is the sort of asset a person could have built a decade of licensing, workshops and consulting on top of. It was handed over instead, and the result is that it has been translated, adapted and reused in ways nobody could have organised deliberately.

The hard part here is not the generosity, it is the work. An explorable explanation is a game, a simulation, an essay and a piece of teaching all at once, and it fails if any of the four is weak. The idea has to be genuinely understood, the interaction has to make the point rather than decorate it, and the whole thing has to survive somebody who arrived from a link and will leave in ten seconds. Forty-two times.

Why it works

The consistent subject is systems that produce outcomes nobody in them intended. Segregation from mild preference. Distrust from reasonable caution. Outrage from ordinary reporting incentives. These are precisely the ideas that argument alone cannot land, because everyone hears them as an accusation and defends themselves.

Handing you the controls dodges that entirely. You are not being told the system does this, you are the one who ran it. The conclusion arrives as something you discovered, which is the only way this particular class of idea has ever changed anybody's mind.

Case has been doing this since 2014 and did more than anyone to make the phrase explorable explanations mean something, then declined to own it. Everything is at ncase.me, free, forever, and yours.

Explorable explanations.

The name of the form Nicky Case did more than anyone to popularise, and then gave away