pixelsBetween

let x,y,val;
function setup() {
  createCanvas(400,400);
  pixelDensity(1);
}

function draw() {
  loadPixels();
  n = 4
  w = 20
  h = 1
  dx = w / width; 
  dy = h / height; 
  x = -w / 2;
  t=2*cos(frameCount/100)
  for (let i = 0; i < width; i += 1) {
    y = -h / 2;
    for (let j = 0; j < height; j += 1) {
      p =t*t/y; 
      q = y+t*x/y
      val = cos(n * sin(p) + q)-cos(q+p-x)//+0.2*tan(q); 
      col = color((val + 1) * 255/2);
      index = 4 * (i + j * width);
      pixels[index] = red(col);
      pixels[index + 1] = green(col);
      pixels[index + 2] = blue(col);
      pixels[index + 3] = alpha(1);
      y += dy;
    }
    x += dx;
  }
  updatePixels();
}