let speed = 2;

let offset = 0;

​

function setup() {

  createCanvas(400, 400);

  noStroke();

  frameRate(30);

}

​

function draw() {

  background(255); // Clear the background on each frame

  offset += speed; // 

​

  // offset cell size reset the loop

  if (offset > cellSize) {

    offset = 0;

  }

​

  for (let y = 0; y < height / cellSize; y++) {

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

      let posX = x * cellSize + offset; //horizontal movement

      let posY = y * cellSize;

​

      fill(random(255), random(255));

​

      //redraw the circle

      ellipse(posX - cellSize, posY, cellSize * 0.8, cellSize * 0.8);

    }

  }

}

​