Here is the code for the two sketches in this video :

// Growing Circle

var taille

function setup() {
  createCanvas(windowWidth,windowHeight)
}

function draw() {
  background(255)

  taille = sin(frameCount*0.005) * height
  circle(width*0.5,height*0.5,taille)
}

// Hue Circle

var teinte, complement

function setup() {
  createCanvas(windowWidth,windowHeight)
  colorMode(HSB,360,100,100,100)
  noStroke()
}

function draw() {

  teinte = 360 + sin(frameCount*0.001) * 360
  background(teinte % 360, 100, 100)

  complement = (teinte + 180) % 360
  fill(complement, 100, 100)
  circle(width*0.5, height*0.5, width*0.5)

}