I Built a Cartoon Open World Driving Game in a Single HTML File

Somewhere in a town that didn’t exist a few weeks ago, a park keeper named Whistles McGraw will pay you to walk ten stray dogs home to him.

You walk up to a dog, it falls in behind you, and by the tenth one you’ve got a line of mutts trailing you down Butterthumb Lane while the traffic idles at a red light. The dogs stay off the road and dodge cars on their own. You couldn’t run one down if you tried.

I made that. I’m still not over it.

It started the way everything starts

I ask myself “what if” constantly. It’s less a strategy than a tic.

What if I could build a word game? Made a few. What if I could build a roller coaster simulator? Built one. What if Minecraft, but mine. What if Super Mario, in 3D. Each one came back a yes, which is the problem with asking, because the yes just makes the next question bigger.

So I asked a stupid one. What if I could build an open world game with Grand Theft Auto vibes in a cartoon-like world?

So my mind went to The Simpsons: Hit & Run, a game I loved and that nobody has really replaced in the twenty-some years since. Drive around a small town, take odd jobs from strange people, wreck things, collect stuff, wander into buildings.

The answer was Public Nuisance. It’s live at games.aiforeveryoneshow.com/mayhem

One file

The whole game is a single HTML file. About 817 KB, 243 KB gzipped. No install, no launcher, no store, no server. You click a link and you’re in a town. Save the file to your desktop, open it with no internet connection at all, and it still runs.

Inside that one file: a procedurally generated town of roughly 250 buildings, a ring highway, a river with bridges and a tunnel through a hill, traffic that obeys actual traffic lights, pedestrians who cross at the crossings and get irritated if you shove past them, a day and night cycle, and a police wanted system with escalating stars.

Also a demolition derby in a floodlit stadium. A fairground with bumper cars and a fully modeled roller coaster you can ride, with a 27 meter lift hill and a real corkscrew inversion. An airfield with a 464 meter runway and a light aircraft that taxis like a car, stalls if you cut the throttle, and lets you eject and parachute out mid-flight.

And a burning tire yard, a penitentiary, a chicken farm, a gothic manor, and a retirement castle, because why wouldn’t there be.

The thing that continues to crack me up

The town has 14 named streets. Gravy Boulevard. Pickleback Street. Sasquatch Road. Disco Badger Way. Named roads run east to west, numbered avenues run north to south, and there’s exactly one Cattywampus Diagonal cutting across the grid.

Every building has a house number. And the numbers are real.

The hundreds digit comes from which block you’re standing on. The tens and units come from how far along that block the building sits. Odd and even are determined by which side of the street you’re on, the way they are in your actual neighborhood. Nothing was typed in. The addressing system derives itself from the geometry of a town that laid itself out.

Almost no player will ever notice this. You’d have to stand at a corner, look at two signs, and do arithmetic for fun. I know it’s there, and knowing it’s there changes how the town feels when I drive through it.

That’s the part of building things that doesn’t show up in any pitch deck. Some of it is just for you.

Nothing was placed by hand

I want to be precise about this, because it’s the piece people misunderstand.

I didn’t design a town. I wrote a generator that designs towns. It’s seeded, so the same seed always produces the same Maplewood, but the roads, the zoning, the buildings, the trees and the props all fall out of the algorithm rather than out of my hands.

Then the landmarks go looking for somewhere to live. The stadium hunts the green belt for a parcel big enough to hold it. The roller coaster walks its own 375 meters of track and checks the entire path for clearance before it commits. If the site doesn’t work, they go find another one.

There are 266 interiors you can walk into, 223 of them private homes, each furnished by room type. Lounges get a television and a sofa. Bedrooms get a bed and a wardrobe. Kitchens get a table and chairs. Every door swings on its hinge. I furnished none of them.

I’m not a developer

I want to say that plainly, because someone will read the paragraph above and assume I’ve been writing shaders in my spare time. I have not. There’s a custom water shader in that river, four summed sine waves quantized into hard toon bands with stepped sun glints, and I could describe what it does to you at a dinner party but I couldn’t write it on a whiteboard.

The whole thing was built conversationally. I described what I wanted. I described what was broken. An AI coding agent built it and verified it, and I looked at the result and said no, the outline needs to fade with distance so the town reads like a drawing instead of plastic. Then we did that.

That’s the loop. Describe, look, react, describe again. The skill it demands isn’t engineering. It’s knowing what you want and being able to say it clearly, which turns out to be much rarer than knowing how to type semicolons.

What actually changed

For most of my life the wall between an idea and a thing was labor. You could have the best idea in the room and it would sit there, because the distance between imagining a town and building one was measured in years and salaries.

That wall came down while a lot of people were busy arguing about whether the tools were any good.

The constraint now is the question. Not the execution, the question. What do you actually want to make? Most people can’t answer that, and it has nothing to do with technology. It’s an imagination muscle, and it atrophies when you spend a career being told what to build instead of asking what could exist.

Mine got its exercise from twenty stray dogs and a park keeper named Whistles McGraw.

I don’t know what I’m building next. I know the question is already forming, and I know that this time the answer will come faster.

Maplewood Mayhem is free and runs in your browser at games.aiforeveryoneshow.com/mayhem. More of what I’ve built with AI lives at ArtificialIntelligence.studio.