let randomCounts = [];

​

function setup() {

  createCanvas(640, 240);

  for (let i = 0; i < 20; i++) {

    randomCounts[i] = 0; 

  }

}

​

function draw() {

  background(255);

​

  //{!2} Pick a random number and increase the count.

  let index = floor(random(randomCounts.length));

  randomCounts[index]++;

​

  stroke(0);

  fill(175);

  let w = width / randomCounts.length;

  //{!3 .offset-top} Graphing the results

  for (let x = 0; x < randomCounts.length; x++) {

    rect(x * w, height - randomCounts[x], w - 1, randomCounts[x]);

  }

}