createCanvas(800, 600)

}

​

function drawWave(y, amplitude, count, phase){

  // y: the vertical position of the *middle* of the waveform

  // amplitude: the height between the top of a peak and depth of a trough

  // count: the number of peaks to be drawn (a.k.a. 'frequency')

  // phase: the amount to shift the wave by horizontally

  beginShape()

  let resolution = 2

  for (var x=0; x<=canvas.width+resolution; x+=resolution){

    vertex(x, amplitude*cos(TWO_PI*count * x/width - phase*count) + y)

  }

  vertex(canvas.width, canvas.height)

  vertex(0, canvas.height)

  endShape(CLOSE)

}

​

var phase = 0

​

function draw() {

  background(0)

  noStroke()

​

  phase += .01 // this controls the speed of the horizontal drift

​

  let amp = 50 // the vertical size of the largest wave

​

  fill(40)

  drawWave(height*.11, amp, 2, -phase/2)

​

  fill('red')

  drawWave(height*.3, amp, 4, phase*2)

​

  fill('orange')

  drawWave(height*.5, amp/2, 8, phase)

​

  fill('yellow')

  drawWave(height*.66, amp/4, 16, phase/2)

}

​