recursion with sand watch

sand_wa

program lab_10;
  uses crt;
  const
    n=60;
    m=16;
  var
   l,i,a,j,k:integer;

  procedure picture1(a,l,t:integer);
    begin
      if t>0 then
        begin
          write('  ');
          picture1(a,l,t-1);
        end
      else
        begin
      write(chr(a+65),chr(a+65));
      if l>0 then
        begin
          l:=l-1;
          picture1(a,l,0);
        end;
        end;
    end;

  procedure sand_watch(a,e,t:integer);
    begin
      if a=e then
        begin
          picture1(a,a,t); writeln;
        end
      else
      begin
      picture1(a,e,t);
      picture1(a,e,t); writeln;
      sand_watch(a-1,e,t+1);
      picture1(a,e,t);
      picture1(a,e,t); writeln;
      end;
    end;

begin
   sand_watch(10,1,0);
end.