срочно помогите по паскалю пожалуйста

[mikl:)]

ето паскаль.

что делают выделеные части?

срочно помогите пожалуста

unit game;

interface
  uses crt;
  function main(kolvo_zaicev:byte):boolean;
   procedure aboyt_mi;
   procedure help;

implementation
const


  sLeft = #17;
  sRight = #16;
  sUp = #30;
  sDown = #31;
  sHead = '%';
  sApple = '@';

  kUp = #72;
  kLeft = #75;
  kDown = #80;
  kRight = #77;

(type    
  TScreenSymbol = record
    Symbol: char;
    Color: byte;
  end;  )            -------------------вот етот раздел

var
  Key, ScanKey: char;
  Time: longint absolute $0040: $006C;
  T: longint;
  HeadX, HeadY, TailX, TailY: integer;
  Direction: (dUp, dLeft, dDown, dRight);   ---------- вот ета строска
  Screen: array [0 .. 49, 0 .. 79] of TScreenSymbol absolute $B800: $0000;
  Lost, Win: boolean;
  oldTail: char;
  x, y,ii,aa, c,ax: integer;



  

function main(kolvo_zaicev:byte):boolean;
begin

  if ax=3 then ax:=0;
   ax:=ax+1;
  c:=0;
  randomize;
  TextMode(259);

  ClrScr;


  gotoxy(1,2);
  for ii:=1 to 79 do
  write('*');

  gotoxy(1,2);
  for ii:=1 to 48 do
  writeln('*');

  gotoxy(1,50);
  for ii:=1 to 79 do
  write('*');


  for ii:=2 to 48 do
  begin
    gotoxy(80,ii);
  writeln('*');
   end;


  HeadX := 40;
  HeadY := 40;
  TailX := 40;
  TailY := 41;
  Direction := dUp;
  Screen[HeadY, HeadX].Symbol := sHead;
  Screen[HeadY, HeadX].Color := 14;
  Screen[TailY, TailX].Symbol := sUp;
  Screen[TailY, TailX].Color := 2;
  Screen[HeadY - 10, HeadX].Symbol := sApple;
  Screen[HeadY - 10, HeadX].Color := 4;
  Lost := false;
  Win:=false;

  repeat

    if KeyPressed then begin
      Key := ReadKey;
      if Key = #0 then ScanKey := ReadKey
      else ScanKey := #0;
    end else begin
      Key := #0;
      ScanKey := #0;
    end;
  (  while T = Time do;
    T := Time -----------------  вот етот кусок
    case ScanKey of
      kUp: if Direction <> dDown then Direction := dUp;
      kLeft: if Direction <> dRight then Direction := dLeft;
      kDown: if Direction <> dUp then Direction := dDown;
      kRight: if Direction <> dLeft then Direction := dRight;
    end;
    case Direction of
      dUp: begin
        Screen[HeadY, HeadX].Symbol := sUp;
        Screen[HeadY, HeadX].Color := 2;
        dec(HeadY);
        if HeadY < 3 then Lost := True;
      end;
      dLeft: begin
        Screen[HeadY, HeadX].Symbol := sLeft;
        Screen[HeadY, HeadX].Color := 2;
        dec(HeadX);
        if HeadX < 2 then Lost := True;
      end;
      dDown: begin
        Screen[HeadY, HeadX].Symbol := sDown;
        Screen[HeadY, HeadX].Color := 2;
        inc(HeadY);
        if HeadY >= 48 then Lost := True;
      end;
      dRight: begin
        Screen[HeadY, HeadX].Symbol := sRight;
        Screen[HeadY, HeadX].Color := 2;
        inc(HeadX);
        if HeadX >= 78 then Lost := True;
      end;
    end;

    case Screen[HeadY, HeadX].Symbol of
      sUp, sLeft, sDown, sRight: Lost := True;

      sApple: begin



                    c:=c+1;
          if c = kolvo_zaicev then   Win := True;

          x := random(70)+5;
          y := random(40)+5;
         Screen[y, x].Symbol := sApple;
        Screen[y, x].Color := 4;
          gotoxy(1,1);
     write('sedenie soba4ki: ',c-1,' iz ', kolvo_zaicev-1,' your level:',ax);


      end;
      else begin
        oldTail := Screen[TailY, TailX].Symbol;

        Screen[TailY, TailX].Symbol := ' ';
        case oldTail of
          sUp: dec(TailY);
          sLeft: dec(TailX);
          sDown: inc(TailY);
          sRight: inc(TailX);
        end;
      end;
    end;

    Screen[HeadY, HeadX].Symbol := sHead;
    Screen[HeadY, HeadX].Color := 14;
  until (Key = #27) or Lost or Win;
           textattr:=$09;
               clrscr;
             

               writeln('                                -------------------');
               Writeln('                                -------------------');
  if Lost then begin  main:=false; WriteLn('                                ||You have lost! ||');  end;
  if Win then begin  main:=true;  WriteLn('                                ||You win!!!     ||');  end;
               writeln('                                -------------------');
               writeln('                                ||vash s4ot:   ',c-1,'||');
               writeln('                                -------------------');
               writeln('                                ||your level:  ',ax,' ||');
               writeln('                                -------------------');
               writeln('                                -------------------');


    readln;

end;
begin
end.