createCanvas(510, 510);

  let r = random(0, 255);

  let g = random(0, 100);

  let b = random(0, 255);

  background(r / 2, g / 2, b / 2);

}

​

let sksize = 10;

let reclocV = 0;

let reclocH = 0;

let column = 2;

let row = 2;

let direction = 1;

​

function draw() {

  noStroke();

  if (direction == 1) {

    if (reclocV < 510) {

      rect(column, reclocV, 100, 1020);

      reclocV++;

    } else {

      direction = 0;

      column = column + 102;

      reclocV = 0;

    }

  } else if (direction == 0) {

    if (reclocH < 510) {

      rect(reclocH, row, 1020, 100);

      reclocH++;

    } else {

      direction = 1;

      row = row + 102;

      reclocH = 0;

    }

  }

  fill(mouseX / 2, mouseX / 6 + mouseY / 6, mouseY / 2, 100);

}

​