{Задание а}

var
  i:integer;
begin
  for i := 90 downto 65 do
    writeln(chr(i), ' ', chr(i), ' ', chr(i), ' ', chr(i));
end.

{Задание б}

var
  i, j:integer;
begin
  for i := 90 downto 65 do
  begin
    for j := 90 downto 65 + 90 - i do
      write(chr(j), ' ');
    writeln;
  end;
end.

{Задание в}

var
  i, j:integer;
begin
  for i := 1 to 9 do
  begin
    for j := 1 to 9 do
      if i = j then
        write(i, ' ')
      else
        write('0 ');
    writeln;
  end;
end.