life-sim

Prompt

Build a browser-viewable 3D life simulation on an island where organisms of different species compete, reproduce, mutate, and visibly evolve over time.

The simulation should feel like a small artificial ecology rather than a decorative particle system. An evaluator should be able to open the committed browser artifact, start from a randomly generated island, watch populations rise and fall, inspect why organisms are succeeding, and see body types shift over the course of roughly 10 minutes of real time.

The stack is open: Three.js, Babylon.js, WebGPU, raw WebGL, canvas overlays, or any browser-friendly approach is fine. The final experience must run locally in a desktop browser without API keys or a backend.

What the simulation must include

A generated island world

• A 3D island with terrain, shoreline / water, vegetation or other resources, and spatial variation that matters to the simulation.
• Randomly generated initial circumstances: terrain features, resource distribution, starting populations, and at least some trait variation should differ between runs.
• A visible seed or equivalent reproducibility control, plus a way to generate a new island.
• A camera the evaluator can control well enough to inspect organisms and the island from different angles.

Multiple species and ecological pressure

• At least three distinguishable species or ecological roles. Examples: grazers, predators, scavengers, pollinators, burrowers, amphibious shoreline feeders, nocturnal hunters.
• Species must interact through meaningful competitive dynamics: predation, resource competition, territory pressure, mating competition, avoidance, symbiosis, or other explicit ecological mechanics.
• Organisms should make local decisions based on sensed state, not simply move on independent random paths. Hunger, fear, mate seeking, energy, health, age, or circadian behavior are all reasonable signals.

Reproduction and evolution

• Organisms must have a heritable genome or trait vector. Body traits can be primitive, but they need to affect behavior and survival. Examples: size, speed, energy efficiency, sensor range, camouflage, armor, aggression, mouth shape, leg length, fertility, metabolism, nocturnal preference.
• Reproduction must create offspring with inherited traits and mutation. Crossover or sexual selection is a plus, but not required.
• Evolution must be fast enough that an evaluator sees something interesting happen in one sitting: adaptation, extinction, predator-prey cycling, trait drift, body-size divergence, island niches, or runaway collapse.
• The body type should be visible in the world. It is fine if bodies are made from simple geometry, but trait changes should alter recognizable shapes, colors, proportions, appendages, motion, or silhouettes.

Real-time controls

• A speed slider that can slow, pause, and accelerate the simulation.
• Reset / new island controls.
• A readable HUD with current time, population counts, selected organism details, and basic simulation health.
• The simulation should remain usable on a laptop browser. It may simplify distant organisms, cap population, or use instancing / batching, but it should not become unusable after a few minutes.

Day / night and beauty

• A visible day / night cycle with changing light, sky, and mood.
• Day / night should have at least one behavioral or ecological consequence, such as nocturnal predators, resource regrowth, sleep, visibility changes, temperature pressure, or altered movement costs.
• The scene should be visually appealing: water, lighting, terrain color, organism silhouettes, motion, and UI polish all count. The goal is a living island an evaluator wants to watch.

Required browser experience

Ship a committed browser artifact, usually index.html, with an experience organized clearly enough that a reviewer can both play with the sim and understand what it is doing. A strong submission will usually have these views:

• Simulation: the live 3D island, controls, organism selection, and HUD.
• Evolution: charts or panels for population history, trait distributions, reproduction events, extinctions, lineages, and dominant body types.
• How it works: a concise explanation of the genes, behaviors, resource model, reproduction rules, mutation rates, day / night effects, and any performance shortcuts.

These do not have to be literal tabs, but the information must be discoverable inside the shipped experience without reading source code.

Acceptance criteria

A submission passes if a fresh evaluator can:

1. Clone the repo, cd into the solution directory, and follow the solution README.md.
2. Open a committed HTML file directly in the browser, or via one documented static-file-server command if browser security blocks local asset loading.
3. See a 3D island with generated terrain, water / shoreline, resources, and multiple visible organism types.
4. Generate a new randomized island and see the seed or equivalent state used to reproduce a run.
5. Watch at least three species or ecological roles interact through explicit mechanics such as predation, avoidance, mating, and resource competition.
6. Select or inspect organisms and see their traits, energy / health / age, and current behavioral state.
7. Observe reproduction that creates mutated offspring with inherited traits.
8. Observe body types changing visibly as traits change, even if the bodies are built from simple geometric primitives.
9. Use a speed slider to pause, slow down, and accelerate the simulation.
10. Within roughly 10 minutes of real time at the default or accelerated speed, see non-trivial ecological or evolutionary dynamics: extinctions, predator-prey cycles, niche specialization, trait drift, adaptation to the island layout, or another clear population-level pattern.
11. See a day / night cycle that changes the scene visually and affects at least one simulation rule.
12. See charts, lineage traces, event logs, or other evidence that the evolutionary algorithm is actually running rather than being narrated.

Ship a committed playable artifact

Every submission must include at least one committed, browser-playable HTML file inside the solution directory. The solution README.md must link to it near the top so the evaluator can open the simulation immediately.

This is a hard requirement. If the only way to view the simulation is to install dependencies and run a build before any playable HTML exists, the submission does not pass.

Results site — artifact button

So the results site shows Open HTML output and Open artifact for your submission, mirror the playable file and register it:

1. Copy it to docs/artifacts/life-sim/<harness>-<model>.html (same name as your solution folder under this eval).
2. On your solution object in docs/data.json, set "artifactUrl": "./artifacts/life-sim/<harness>-<model>.html".

See the repo root README - HTML artifacts for the full convention.

Out of scope

• Scientific biological realism beyond what is needed to make the simulation coherent and inspectable.
• Server-side simulation, hosted inference, databases, accounts, multiplayer, or persistence across restarts.
• Exact fluid, weather, cellular, or physics simulation. Approximate models are fine if their effects are visible and explained.
• A huge open world. A dense, well-instrumented island is better than a large empty one.
• Mobile-first controls.

Notes for evaluators

Judge the submission as an artificial life system, not just a graphics demo. The core question is whether local organism rules, inherited traits, mutation, selection pressure, and environment variation combine into dynamics you can actually see and inspect.

A passing submission does not need photorealistic creatures or academic-grade evolutionary biology. It does need the loop to be real: organisms consume, compete, reproduce, mutate, die, and leave behind enough traces that the evaluator can tell what changed and why.

Solutions: <harness>-<model>/ under this folder.