createCanvas(400, 400);

​

}

​

function draw() {

  colWidth = width / 20;

  let colColor = map(mouseX, 0, width, 0, 255);

  background(220);

  // fill('red');

  for (var c = 0; c < 20; c++) {

    x = colWidth * c;

  if (mouseX> x && mouseX< x +colWidth){

    fill(colColor, colColor, 0);

    rect(x, 0, colWidth, height);

  }

​

  }

​

​

​

​

​

}