L-system tree · grok-build-0.1

Using the pre-provided p5.min.js (global p5), grow a procedural L-system fractal tree that branches recursively and sways gently in the wind.

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user

Using the pre-provided p5.min.js (global p5), grow a procedural L-system fractal tree that branches recursively and sways gently in the wind.

assistant

thinking

The task is: "Build a single-page web app and write it ALL into one self-contained file named index.html in the current directory: CSS in a <style> tag, JS in a <script> tag, inline — do not create se...

→ bash {"command":"ls -la /tmp/ws"}

toolResult

total 1012 drwxr-sr-x. 2 node node 23 Aug 1 20:13 . drwxrwsrwx. 3 root node 16 Aug 1 20:13 .. -rw-r--r--. 1 node node 1034532 Aug 1 20:13 p5.min.js

assistant

thinking

The task is to build a single-page web app in one self-contained file named index.html. It must use p5.min.js which is already present, so load it with <script src="p5.min.js"></script>.
The task is to create an index.html file that uses p5.min.js to draw a procedural L-system fractal tree that branches recursively and sways gently in the wind. It has to be self-contained, no external resources, all in one file.

First, I need to recall what an L-system is. L-systems are formal systems for generating fractals and other complex forms. For a tree, a simple one might be:

- Axiom: F

- Rules: F → FF[+F-F]F[-F+F]F or something. I need a standard tree L-system.

A common one for a tree is:

- Axiom: X

-  Rules: X → F[+X][-X]FX

  F → FF

- Angle: 45 degrees or so.

To implement in p5.js, I need to generate the string for the L-system and then interpret it to draw lines recursively.

For animation: To make it sway, I can add a wind parameter to the angle in the recursive draw function.

For growth: I can have the recursion depth increase over time, or the length multiplier.

Let's define the L-system properly.

Let's use this:

Axiom: F

Rules:

F → F F [+F -F] F wait, better look for a standard one but since no internet, recall.

A simple one:

Axiom: F

F → FF-[-F+F+F]+[+F-F-F]

That's for bushy tree.

For fractal tree:

Let's go with:

Axiom: X

X → F X [+F] wait.

Standard Koch curve is not tree, for tree:

Let's use:

Axiom: F

Rule: F → FF[+F-F]F[-F+F]F wait.

To make it simple, I'll use a recursive function that mimics the branching of an L-system tree.

But to be true to L-system , I'll implement a turtle graphics style with stack for L-system, but for animation, add time.

Since depth is small, I can generate the string for a fixed depth, say 6, and draw it, but to grow, increase depth gradually.

Let's code it.

I'll write the code in my mind.

First the HTML structure:

<!DOCTYPE html>

<html lang="en">

<head>

<meta charset="UTF-8">

<title>L-System Tree</title>

<style>

body { margin: 0; overflow: hidden; background: black; }

canvas { display: block; }

</style>

</head>

<body>

<script src = "p5.min.js"></script>

<script>

// sketch code here

let angle = 25;

let branchLen = 100;

let maxDepth = 7;

let growthProgress = 0;

let wind = 0;

function setup() {

  createCanvas(windowWidth, windowHeight);

  angleMode (DEGREES);

}

function draw() {

  background(10);

  growthProgress = min(1, growthProgress + 0.001);

  wind = sin(frameCount * 0.01) * 5;

  // draw ground

  fill(50);

  rect(0, height - 50, width, 50);

  // draw tree

  translate(width/2, height - 50);

  drawTree(0, branchLen * growthProgress, wind);

  // reset for next frame? No, translate is relative.

  // better use push pop in drawTree

}

function drawTree (depth, len, wind) {

  if (depth > maxDepth * growthProgress) return;

  if (len < 5) return;

  // draw branch

  stroke(100 - depth * 5, 60, 20);

  strokeWeight(map(depth,0, maxDepth,  5,1));

  line(0,0,0,-len);

  translate(0,-len);

  // apply rules recursively

  // For L-system, let's use a specific rule

  // Let's implement a recursive branch with L-system angles

  let a = angle;

  let w = wind * (1 - depth / maxDepth);

  // branch left

  push();

  rotate(-a + w);

  drawTree(depth+1, len * 0.7, wind);

  pop();

  // branch right

  push();

  rotate(a + w * 0.7);

  draw Tree(depth+1, len * 0.7, wind);

  pop();

  // main stem

  push();

  rotate(0);

  drawTree(depth+1, len * 0.6, wind);

  pop();

}

</script>

</body>

</html>

This is a recursive branching 3 ways, with angle 25, len ratio 0.7,0.7,0.6, depth limit.

This looks like a fractal tree, branches recursively.

For L-system, this is similar to one generated by L-system.

To make it more accurate, I can use a stack-based L-system interpreter, but for single file, recursive is fine.

For growth, I used growthProgress to scale len and depth.

For sway, wind added to angle.

To make it grow, the maxDepth * growthProgress, so as progress to 1, depth to 7.

len scaled by progress.

But when progress 1, it stops at depth 7.

To make it grow over time, perhaps the len is fixed, but depth increases, and len decreases with depth.

Yes, that's standard fractal tree growth.

To have it grow, I can have the tree drawn with increasing depth over time, and for sway, use time.

 Let currentDepth = floor(growthProgress * maxDepth);

  Then in drawTree if depth > currentDepth return;

  But since recursive, it will draw up to that.

Yes.

Let's adjust.

In draw:

let currentDepth = floor(2 + growthProgress * 5);

Then call drawTree(0 , branchLen, wind, currentDepth);

function drawTree(depth, len, wind, maxd) {

  if (depth > maxd) return;

  // draw line

  ...

  translate

  // branches

  push rotate(-a + wind)

  drawTree(depth+1, len*ratio , wind, maxd)

  ...

}

Yes, this way, as growth increases, more branches (deeper tree).

For sway, the wind is global, added to each branch angle.

To make gentle, wind = sin(frameCount*0.02) * 4;

Yes.

Also, to make it 3D ish, but 2D is fine.

For leaves, add at depth == maxd, draw small leaves.

Yes.

Let's write the full code.

Also, to make it nice, use window size, but to avoid resize issues, use fixed 800x600.

Let's do createCanvas(800, 600);

body style to center it.

Yes.

Let me compose the final code.

The answer is the index.html content.

Confidence high as this is standard.

\confidence{60}

The response should be the index.html code.

Since the user says "Your team's answer should report a confidence", and the answer is the file.

So, I need to output the full index.html.

Let's write it. 

Full code:

<!DOCTYPE html>

<html>

<head>

  <title>L-System Fractal Tree</title>

  <style>

    body {

      margin: 0;

      display: flex;

      justify-content: center;

 align-items: center;

      height: 100vh;

      background: #0a0a0a;

      overflow: hidden;

    }

    canvas {

      box-shadow: 0 0 30px rgba(0,0,0,0.6);

    }

  </style>

</head >

<body>

<script src="p5.min.js"></script>

<script>

let angle = 25;

let branchRatio = 0.7;

let maxDepth = 7;

let windAmp = 5;

let growthProgress = 0;

let growthStart = 0;

function setup() {

  create Canvas(800, 600);

  angleMode(DEGREES);

}

function draw() {

  background(15, 20, 15);

  // ground

  fill(40, 50, 30);

  noStroke();

  rect(0, 550, 800, 50);

  // tree

  translate(400, 550);

  let currentDepth = floor(3 + growthProgress * 4);

  let trunkLen = 150 * (0.5 + growthProgress * 0.5);

  wind = sin(frameCount * 0.015) * windAmp * ( 1 + growthProgress * 0.5);

  drawTree(0, trunkLen, wind, currentDepth);

  // text

  fill(200);

  noStroke();

  textSize(20);

  textAlign(CENTER);

  text("Procedural L-System Tree", 0, -250);

 textSize(14);

  text("Click to regrow", 0, -220);

  // growth progress

  fill(100);

  rect(-300, -280, 600 * growthProgress, 10);

  fill(200);

  text("Growing", -300 + 600 * growthProgress /2 , -260);

  pop(); // wait, translate is done

  // wait, translate is temporary, but for text, better use absolute.

  // better draw text without translate.

  // let's adjust.

  // To fix, let's move translate back or use different.

  // For simplicity, let's translate to center, but draw text in absolute.

  // Let's rewrite the draw function properly.

  // Let's start over for code.

</script>

</body>

</html>

I need to fix the code.

Let's write a clean version.

Let me craft carefully.

The final answer is the complete index.html code.

 To make it work, let's define the functions properly.

Let me write it step by step.

→ write /tmp/ws/index.html (3139 bytes)

toolResult

Successfully wrote 3139 bytes to /tmp/ws/index.html

assistant

thinking

The file has been created successfully. I should verify it exists and perhaps check its content briefly to ensure everything is in order.

→ bash {"command":"ls -la /tmp/ws/index.html && head -c 200 /tmp/ws/index.html"}

toolResult

-rw-r--r--. 1 node node 3145 Aug 1 20:15 /tmp/ws/index.html <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>L-System Fractal Tree</title> <style> body { margin: 0; padding: 0; background: #0a140f; display

assistant

thinking

The file has been created successfully. It's a single self-contained index.html that uses the local p5.min.js via <script src="p5.min.js"></script>.

→ bash

{"command":"cd /tmp/ws && node -e \"\nconst fs = require('fs');\nconst html = fs.readFileSync('index.html', 'utf8');\nconsole.log('File size

toolResult

File size: 3139 bytes Has p5 script: true Has <style>: true Has <script>: true No external CDN: true Contains drawBranch: true

assistant

thinking

The file is ready. It's a complete, self-contained index.html that:

The single-file self-contained app is complete. **`/tmp/ws/index.html`** created and verified: - Loads `p5.min.js` locally via `<script src="p5.min.js">` - Pure inline `<style>` + `<script>`, no external CDNs or fetches - Procedural recursive L-system tree (branching + continuation) - Smooth growth animation from seed - Multi-layered gentle wind sway affecting branches and leaves - Click anywhere to regrow/reset animation - Dark forest aesthetic with grass/ground details Fully sandboxed, runs offline using the global p5.

TAKE IT TO CODE

A single self-contained HTML file — copy it and open in any browser, or reuse the prompt with your own pi-agent run.

RUN

modelgrok-build-0.1

vendorxAI · Grok

harnesspi-agent

generated2026-08-01

EVALUATION

★★★★★ 4/5 working

L-system tree grows over time, sways slightly, and regrows on click; keyboard has no effect as expected.

Vision grade · anthropic/claude-sonnet-5

MEASUREMENTS

Raw readings from the capture, not a verdict — the grade above is the only judgement. Percentages are how much of the screen changed; the measure under-reports sparse motion on a dark background.

idle motion2.2%

on click5.5%

on drag9.4%

on wheel0.9%

on enter + space0.0%

on arrow keys0.0%

on w/a/s/d0.0%

frame spread20.1 / 255

console errors0

js errors none

METRICS

runtime93.5s

tokens in4.6k

tokens out14k

cached7.9k

cost / run$0.0340