function setup() {

  createCanvas(500, 500);

}

​

function draw() {

  background(225);

  for(let i=0; i<split; i++) {

    drawVerticalLine((width/split)*i + (width/split));

    drawHorizontalLine((height/split)*i + (height/split));

  }

}

​

function drawVerticalLine(x) {

  line(x, 0, x, height);

}

​

function drawHorizontalLine(y) {

  line(0, y, width, y);

}