Emergent Evolver

What it is

Emergent Evolver hands you a body editor — joints, bones, muscles, feet, a head — and then gives your creature to a neural network that starts from pure noise. There’s no animation in here anywhere, and no scripted walk cycle. Twenty-odd creatures have a go at the course, the best few breed, and the network grows brand new neurons and connections as it goes.

After a few dozen generations something drags itself forward. After a few hundred, something runs. Watching that happen the first time is genuinely one of my favourite things I’ve ever built.

The parts I am proud of

You can watch it think

The brain panel draws the whole network live: senses down the left, muscles down the right, the grown neurons in between, and every wire lights up as it fires. The gait panel shows you which muscle pulls when, so you can literally watch a walk turn into a run. Most neuroevolution demos just show you the result — I wanted you to see the machinery!

A map of every way of moving

Evolution keeps one answer and throws everything else in the bin — including the creature that hopped instead of walking and finished two metres behind. That always bugged me, it felt like a loss. So the gait archive keeps them ALL: a grid sorted by how a creature moves instead of how far it got, holding the best hopper, the best crawler and the best sprinter right next to each other. Click any square to watch it. Breed from it if you like it better than the winner!

Editing the body without wiping the brain

Add a tail to a creature you’ve trained for a thousand generations and it carries everything it knows across, rewiring itself around the new limb instead of starting over from noise. This was by far the hardest part to get right, and it’s the thing that makes the whole toy actually fun to play with instead of frustrating.

Physics that makes cheating not work

A foot grips the ground and absorbs a landing. A bare joint scuffs and loses speed, so a creature that tries to walk on its shins pays for it. Muscles get tired when you hold them. And if the head touches the ground, the run is over.

None of that is a scoring penalty though! It’s all just built into the world, so the exploits stop working instead of getting punished after the fact. That difference matters way more than I expected: penalise a behaviour and evolution will find a way to do it just under the limit. Make it physically not worth doing and evolution stops trying altogether.

Six courses, six brains

Running, jumping, obstacles, climbing, gaps, swimming. Every creature can have a go at all of them and keeps a separate brain for each one — so teaching it to swim costs it nothing back on land.

No install, no account, no engine

The entire thing is ONE HTML file, about 400KB, with zero dependencies. Everything saves right in your browser, and any creature exports as a single line of text you can paste back in anywhere. Send your best one to a friend!