public class MainForm() extends JFrame {
  public MainForm() {
    super();
    int cellSize = 50;
    java.awt.Container content = getContentPane();
    Dimension fieldSize = new Dimension(cellSize * 4, cellSize * 4);
    content.setPreferredSize(fieldSize);
    pack();
    int k = 0;
    for (int i = 0; i < Cells.length - 1; i++) {
      for (int j = 0; j < Cells[i].length - 1; j++) {
        Cell newCell = new Cell();
        newCell.setSize(cellSize, cellSize);
        newCell.setLocation(cellSize * i, cellSize * j);
        newCell.setValue(k++);
        content.add(newCell);
      }
    }
  }
}

content.setLayoutManager(null)