user: Create an html and javascript basic phisycs simulations with balls that fall with gravity and bounce and collisionate each others, and let editable on the code, variables like numbers of balls, sizes, gravity, force and quantity

assistant: Here's an example of how you could create a simple physics simulation in HTML and JavaScript using canvas element to draw the scene. The simulation will allow you to change variables such as number of balls, size, gravity, force, and quantity.
```php
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Physics Simulation</title>
    <script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
    <link rel="stylesheet" href="style.css">
</head>
<body>
    <canvas id="canvas" width="500" height="400"></canvas>
    <script src="script.js"></script>
</body>
</html>
```
And here's some sample CSS for styling the canvas:
```css
canvas {
  border: 1px solid black;
}
```
And here's the script.js file where we'll write our simulation logic:
```javascript
const canvas = document.getElementById("canvas");
const ctx = canvas.getContext("2d");

// Constants
const WIDTH = 500;
const HEIGHT = 400;
const GRAVITY = 9.8;
const BALL_RADIUS = 5;
const NUM_BALLS = 20;

// Variables
let balls = [];

function simulate() {
  // Clear canvas
  ctx.clearRect(0, 0, WIDTH, HEIGHT);
  
  // Draw balls
  balls.forEach((ball) => {
    drawBall(ball);
  });
  
  // Update positions
  updatePositions();
  
  // Request animation frame
  requestAnimationFrame(simulate);
}

function drawBall(ball) {
  const x = ball.x * Math.cos(ball.angle) - ball.y * Math.sin(ball.angle);
  const y = ball.x * Math.sin(ball.angle) + ball.y * Math.cos(ball.angle);
  
  ctx.beginPath();
  ctx.arc(x, y, BALL_RADIUS, 0, Math.PI*2);
  ctx.fillStyle = "white";
  ctx.fill();
}

function updatePositions() {
  balls.forEach((ball) => {
    moveBall(ball);
    rotateBall(ball);
  });
}

function moveBall(ball) {
  const dx = ball.x * Math.cos(ball.angle) - ball.y * Math.sin(ball.angle);
  const dy = ball.x * Math.sin(ball.angle) + ball.y * Math.cos(ball.angle);
  
  if (dx!= 0 || dy!= 0) {
    ball.x += dx / GRAVITY; 
    ball.y += dy / GRAVITY;
    
    if (ball.x > WIDTH || ball.x < 0) {
      ball.x -= dx;
    }
    
    if (ball.y > HEIGHT || ball.y < 0) {
      ball.y -= dy;
    }
  }
}

function rotateBall(ball) {
  ball.angle += Math.PI/100;
}

function addBall() {
  const newBall = {
    x: Math.random() * WIDTH,
    y: Math.random() * HEIGHT,
    angle: Math.random() * Math.PI*2,
  };
  balls.push(newBall);
}

$(document).ready(()=>{
  setInterval(addBall, 50);
});
```
This code creates a canvas element, sets up the constants and variables, and defines functions to handle drawing individual balls, updating all the positions, moving the balls based on their angles and gravity, and rotating the balls. It also has a function `addBall` which adds a new ball to the array every 50ms. You can adjust these intervals or any other variable to suit your needs.
Please note this is just one way to implement it and there are many ways to achieve the same result.

user: Can you simplify your example a bit?

assistant: It first should give the steps like:
To create a simple physics simulation in HTML and JavaScript using canvas element and other details you've provided, follow these steps:
1. Create 2 files:
a. index.html
b. app.js

Start with index.html, for example:
<CODE>

app.js:
<CODE>

This code creates a canvas element, sets up the constants and variables, and defines functions to handle drawing individual balls, updating all the positions, moving the balls based on their angles and gravity, and rotating the balls. It also has a function addBall which adds a new ball to the array every 50ms. You can adjust these intervals or any other variable to suit your needs.
Please note this is just one way to implement it and there are many ways to achieve the same result.