createCanvas(400, 400);

}

​

function draw() {

  background(255);

  var step = height / 14;

  for(var i = height; i > 0; i-= step){

    var black = color(0, 0, 0);

    var white = color(255, 255, 255);

    var c = lerpColor(black, white, i / height);

    fill(c);

    var off = 20;

    rectMode(CORNERS);

    rect(i , height - i - 20, i + step, height); 

  }

}