for (let i = 0; i <= 6; i+= 3) {
  for (let j = 0; j <= 6; j+= 3) {
    (checkReg(i, j, grid))
    var tempArr = [];
    let x = i;
    for (x; x < i + 3; x++) {
      let y = j;
      for (y; y < j + 3; y++) {
        tempArr.push(grid[x][y])
      }
    }
    console.log(tempArr);
  }
}