// Daniel Shiffman

// http://natureofcode.com

​

const heights = [];

let sd = 0.5;

let sd_dir = 0.01;

​

function setup() {

  createCanvas(640, 240);

}

​

function draw() {

  background(255);

  const e = 2.71828183; //"e", see http://mathforum.org/dr.math/faq/faq.e.html for more info

  let m = 0; //default mean of 0

  for (let i = 0; i < width; i++) {

    let xcoord = map(i, 0, width, -3, 3);

    let sq2pi = sqrt(2 * PI); //square root of 2 * PI

    let xmsq = -1 * (xcoord - m) * (xcoord - m); //-(x - mu)^2

    let sdsq = sd * sd; //variance (standard deviation squared)

    heights[i] = (1 / (sd * sq2pi)) * pow(e, xmsq / sdsq); //P(x) function

  }

​

  sd += sd_dir;

  if (sd > 2 || sd < 0.3) sd_dir *= -1;

​

  // a little for loop that draws a line between each point on the graph

  stroke(0);

  strokeWeight(2);

  noFill();

  beginShape();

  for (let i = 0; i < heights.length - 1; i++) {

    let x = i;

    let y = map(heights[i], 0, 1, height - 2, 2);

    vertex(x, y);

  }

  endShape();

}

​