function initDataGrid() {
  grid.length = 0;
  for (var y = 0; y < ROWS + 4; y++) {
    grid[y] = newDataRow();
  }
}
// Initialize the 2D data grid with nulls.
Initialize the 2D data grid with nulls.
Initialize the 2D data grid with nulls .
function initDataGrid() {
  grid.length = 0;
  for (var y = 0; y < ROWS + 4; y++) {
    grid[y] = newDataRow();
  }
}
function initDataGrid ( ) { grid . length = 0 ; for ( var y = 0 ; y < ROWS + 4 ; y ++ ) { grid [ y ] = newDataRow ( ) ; } }
Initialize the 2D data grid with nulls.
Initialize the 2D data grid with nulls .