let w;

let swSize= 360/ numSwatches; 

​

function setup() {

  createCanvas(800, 400);

  colorMode(HSB, 360, 100, 100)// 360 color of circle, 0-100 saturation, 0-100 brightness

  w =width/ numSwatches;

  noStroke();

}

​

function draw() {

  background(220);

  for(let sw=0; sw < numSwatches; sw++) {

    let x = sw * w

    let h = sw * swSize

    fill(h,100,100);

      rect(x,0, w, height)

  }

}