const NUM = 9

const col = 3

const size = 30

const pad = 10

const box = (x, y) => Object.assign(

  document.body.appendChild(

    document.createElement('div')

  ).style, {

    position: 'absolute',

    width: size + 'px', 

    height: size + 'px',

    top: y + 'px', 

    left: x + 'px',

    background: 'red'

})

const off = (size + pad)

for (let i = 0; i < NUM; i++) {

  const x = (i % col) * off

  const y = parseInt(i / col, 10) * off

  box(x, y)

}