// Daniel Shiffman

// The Nature of Code

// http://natureofcode.com

​

// A random walker object!

​

var x, y, prevX, prevY;

​

function setup() {

    createCanvas(windowWidth, windowHeight);    

    x = width/2;

    y = height/2;

    prevX = x;

    prevY = y;

    background(0);

}

​

function draw() {

    stroke(255);

    line(prevX,prevY,x, y);

​

    prevX = x;

    prevY = y;

    var stepx = random(-1, 1);

    var stepy = random(-1, 1);

    var stepsize = montecarlo()*50;

    stepx *= stepsize;

    stepy *= stepsize;

    x += stepx;

    y += stepy;

    x = constrain(x, 0, width-1);

    y = constrain(y, 0, height-1);

}

​

function montecarlo() {

  while (true) {    

​

    var r1 = random(1); 

    var probability = pow(1.0 - r1,8);  

​

    var r2 = random(1); 

    if (r2 < probability) { 

      return r1;

    }

  }

}