unit Unit1;

{$mode objfpc}{$H+}

interface

uses

  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls;

type

  { TForm1 }

  TForm1 = class(TForm)

    Button1: TButton;

    procedure Button1Click(Sender: TObject);

    procedure FormMouseDown(Sender: TObject; Button: TMouseButton;

      Shift: TShiftState; X, Y: Integer);

    procedure FormPaint(Sender: TObject);

  private

    { private declarations }

  public

    { public declarations }

  end;

const

  columns = 4;

  rows = 4;

  diameter = 40;

var

  Form1: TForm1;

  board: array[0..rows, 0..columns] of boolean;

implementation

{$R *.lfm}

procedure TForm1.FormPaint(Sender: TObject);

var

  r, c: integer;

begin

  for r := 0 to rows-1 do begin

    for c := 0 to columns-1 do begin

      if board[r, c] then begin

        Canvas.Brush.Color := clBlue;

      end else begin

        Canvas.Brush.Color := clYellow;

      end;

      Canvas.Ellipse(c*diameter, r*diameter, (c+1)*diameter, (r+1)*diameter);

    end;

  end;

end;

procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;

  Shift: TShiftState; X, Y: Integer);

var

  r, c: integer;

begin

  c := X div diameter;

  r := Y div diameter;

  if (r>=0) and (c>=0) and (r

    board[r, c] := not board[r, c];

    if r > 0 then board[r-1, c] := not board[r-1, c];

    if r < rows-1 then board[r+1, c] := not board[r+1, c];

    if c > 0 then board[r, c-1] := not board[r, c-1];

    if c < columns-1 then board[r, c+1] := not board[r, c+1];

  end;

  Refresh;

end;

procedure TForm1.Button1Click(Sender: TObject);

var

  i: integer;

  x, y: integer;

begin

  for i := 0 to 100 do begin

    x := round(Random * columns * diameter);

    y := round(Random * rows * diameter);

    FormMouseDown(nil, mbLeft, [], x, y);

  end;

end;

end.