Very cool: New York City is developing a next-generation playground, designed to create new ways of spurring the imagination of kids. It’s being designed for free by David Rockwell, the architect who also designed the sushi restaurant Nobu and the Mohegan Sun casino, and it’s based on an interesting critique of today’s playgrounds: They are focused too narrowly on children’s physical activity, and don’t encourage other forms of social play or fantasy play.

So what will the avante-garde playground look like? According to today’s New York Times:

Developers of the Lower Manhattan project envision groups of children collaborating, for instance, loading containers with sand, hoisting them up with pulleys and then lowering them down to wagons waiting to be wheeled off to another part of the park.

What may sound like a training ground for tiny construction workers actually holds huge developmental benefits, backers say. “You have a level of interaction that you would never have with fixed parts,” Mr. Hart said.

Playground design is such a wickedly cool subgenre of architecture. One of the things that makes me sad as I visit New York’s playgrounds with my one-year-old is noticing how many wildly fun things have vanished from the playgroundosphere over the last twenty years, removed by city officials nervous about lawsuits. I remember back in the late 70s, when the first wave of playground-revitalization hit Canada, and bland monkeybars-and-swings play areas were replaced with trippy, massive wooden constructions: Tree-fort-style houses on stilts, connected up by long platforms, bridges, and day-glo plastic tubes. A few blocks from my house there was something even crazier: A massive jumble of telephone-pole-like wooden pillars, all leaning at crazy angles together as if a giant had tried to cram them into the ground straight but they’d fallen all over one another. It was a total blast to clamber around it; you could go straight to the core and hide in the nooks created by the pillars (superb for distant-planet fantasy play, lemme tell you), or climb out to the edge of an individual pillar, which might jut out 10 feet in the air at a 60-degree angle. It was gloriously fun, infinitely creative — and, of course, a total deathtrap. At some point, a Toronto lawyer clapped his eyes on this thing, envisioned a million-dollar lawsuit from some kid paralyzed during a play-session, and the thing, alas, was promptly razed to the ground.

The sad thing is that some of the most dangerous playground toys also induced superb play. Remember the see-saw? I used to spend hours at my Canadian cottage playing on my uncle’s massive, 12-foot-long see-saw. Seesaws were the best training in basic physics you could possibly imagine, because you could scoot up and down the seesaw to figure out where precisely you needed to sit to be able to counterbalance a lighter child. Or you could stack a bunch of smaller kids on one side and see how much bigger a kid you could lift in the air. You learned, in essence, Archimedes’ insight about lever dynamics: “Give me a lever long enough and a fulcrum on which to place it, and I shall move the world.”

But you can’t find a single seesaw anywhere in New York any more, because there’s no way they could survive liability claims. Sure, seesaws are a superb mechanism for producing the sort of veritiginous play that ludologist Roger Caillois called “illinx” — the act of voluntarily and joyfully discombobulating your senses. But any activity that produces illinx eventually produces physical injuries, too, and there are more lawyers than taxis in Manhattan. Back in the day, in fact, we often intentionally assaulted each other with seesaw pranks, such as getting the other kid high in the air — then jumping off and letting him crash to the ground. Ouch! I’ll sue!

Even though I have no desire to have my kid suffer massive headwounds, it’s a little sad that he won’t be able to experience the same physics-experiment aspect of seesaws. So if there’s any way Rockwell can produce an outdoor playspace that recaptures any of this spirit, I’m in favor of it. Give kids a fun enough playground and you can move the world.