unit Unit1;

{$mode objfpc}{$H+}

interface

uses

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

  ExtCtrls;

type

  { TForm1 }

  TForm1 = class(TForm)

    Button1: TButton;

    Timer1: TTimer;

    procedure Button1Click(Sender: TObject);

    procedure FormMouseDown(Sender: TObject; Button: TMouseButton;

      Shift: TShiftState; X, Y: Integer);

    procedure FormPaint(Sender: TObject);

    procedure Timer1Timer(Sender: TObject);

  private

    { private declarations }

  public

    { public declarations }

  end;

const

  rows = 20;

  cols = 30;

  size = 20;

var

  Form1: TForm1;

  field1, field2: array [0..cols, 0..rows] of boolean;

implementation

{$R *.lfm}

function getCell(x, y: integer): integer;

begin

  Result := 0;

  x := (x + cols) mod cols;

  y := (y + rows) mod rows;

  if field1[x, y] then Result := 1;

end;

procedure TForm1.FormPaint(Sender: TObject);

var

  i, j: integer;

begin

  Canvas.Brush.Color := clBlack;

  for i := 0 to cols-1 do begin

    for j := 0 to rows-1 do begin

      Canvas.MoveTo(i*size, (j+1)*size);

      Canvas.LineTo((i+1)*size, (j+1)*size);

      Canvas.LineTo((i+1)*size, j*size);

      if field1[i, j] then Canvas.Ellipse(i*size, j*size, (i+1)*size, (j+1)*size);

    end;

  end;

end;

procedure TForm1.Button1Click(Sender: TObject);

begin

  Timer1.Enabled := not Timer1.Enabled;

end;

procedure TForm1.Timer1Timer(Sender: TObject);

var

  i, j, count: integer;

begin

  for i := 0 to cols-1 do begin

    for j := 0 to rows-1 do begin

      count := 0;

      count := count + getCell(i-1, j-1);

      count := count + getCell(i-1, j);

      count := count + getCell(i-1, j+1);

      count := count + getCell(i, j-1);

      count := count + getCell(i, j+1);

      count := count + getCell(i+1, j-1);

      count := count + getCell(i+1, j);

      count := count + getCell(i+1, j+1);

      if field1[i, j] then begin

        field2[i, j] := (count=2) or (count=3);

      end else begin

        field2[i, j] := count=3;

      end;

    end;

  end;

  field1 := field2;

  Refresh;

end;

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

  Shift: TShiftState; X, Y: Integer);

var

  i, j: integer;

begin

  i := x div size;

  j := y div size;

  if (i < cols) and (j < rows) then field1[i, j] := not field1[i, j];

  refresh;

end;

end.