createCanvas(400, 400);

}

​

function draw() {

  background(220);

  for (let x = 0; x < width; x += 40) {

    if (mouseX > x && mouseX < x+ 40) {

      fill("red");

      rect(x, 0, 40, height);

    } else {

      fill("white");

        rect(x, 0, 40, height);

    }

  }

}

// is the mouse greath than the x position than is it greater than 40 which is the piel of the one column