Чертаене на правоъгълник в Pascal

    Program box;
    uses Crt;
    (*your procedure same as the procedure window in the crt unit...*)
    procedure draw(x1,y1,x2,y2:integer);
       (*local procedure line1*)
       procedure line1(a,b,c,e:integer);
       (*writes a - line to the screen*)
       (*a and b are the starting position*)
          begin
          gotoxy(a,b);
          while c <= e do begin
             inc(c,1);
             write(#196);
          end;
       end;(*end of line1*)
       (*local procedure line2*)
       (*this writes a | line to the screen*)
       procedure line2(a,b,c,e:integer);
       begin
            while c <= e do begin
                gotoxy(a,b);
                write(#179);
                inc(c,1);
                inc(b);
            end;
       end;(*end of line2*)
    begin
       gotoxy(x1,y1);(*upper left corner of the box*)
       write(#218);
       gotoxy(x2,y1);(*upper right corner of the box*)
       write(#191);
       (*let's go back to the upper left corner*)
       (*and concatenate the upper corners...*)
       line1(x1+1,y1,x1,x2-2);
       gotoxy(x2,y2);(*lower right corner of the box*)
       write(#217);
       gotoxy(x1,y2);(*lower left corner of the box*)
       write(#192);
       line1(x1+1,y2,x1,x2-2);(*concat the lower corners*)
       line2(x1,y1+1,y1,y2-2);(*concat the left sides of the box*)
       line2(x2,y1+1,y1,y2-2);(*and last,concat the right sides too*)
    end;
    begin
     clrscr;
     draw(5,1,20,20);
     readln;
    end.