CROSS JOIN ordering

I am curious what is proper ordering for cross joining and joining at
all for two tables. I look at the example at
http://www.postgresql.org/docs/9.0/static/queries-table-expressions.html
and there is:

SELECT * FROM t1 CROSS JOIN t2;num | name | num | value
-----+------+-----+-------  1 | a    |   1 | xxx  1 | a    |   3 | yyy  1 | a    |   5 | zzz  2 | b    |   1 | xxx  2 |
b   |   3 | yyy  2 | b    |   5 | zzz  3 | c    |   1 | xxx  3 | c    |   3 | yyy  3 | c    |   5 | zzz
 
(9 rows)

I thought that this should be rather:
  1 | a    |   1 | xxx  2 | b    |   1 | xxx  3 | c    |   1 | xxx  1 | a    |   3 | yyy  2 | b    |   3 | yyy  2 | b
|   3 | yyy  1 | a    |   5 | zzz  2 | b    |   5 | zzz  3 | c    |   5 | zzz
 

DROP TABLE t1, t2;
CREATE TABLE t1 (num int, char name);
CREATE TABLE t2 (num int, value varchar(3));
INSERT INTO t1 VALUES (1, 'a'), (2, 'b'), (3, 'c');
INSERT INTO t2 VALUES (1, 'xxx'), (2, 'yyy'), (3, 'zzz');

SELECT * FROM t1 CROSS JOIN t2;num | char | num | value
-----+------+-----+-------  1 | a    |   1 | xxx  2 | b    |   1 | xxx  3 | c    |   1 | xxx  1 | a    |   2 | yyy  2 |
b   |   2 | yyy  3 | c    |   2 | yyy  1 | a    |   3 | zzz  2 | b    |   3 | zzz  3 | c    |   3 | zzz
 
(9 rows)

or even (same data as in documentation):

DROP TABLE t1, t2;
CREATE TABLE t1 (num int, char name);
CREATE TABLE t2 (num int, value varchar(3));
INSERT INTO t1 VALUES (1, 'a'), (2, 'b'), (3, 'c');
INSERT INTO t2 VALUES (1, 'xxx'), (3, 'yyy'), (5, 'zzz');

SELECT * FROM t1 CROSS JOIN t2;num | char | num | value
-----+------+-----+-------  1 | a    |   1 | xxx  2 | b    |   1 | xxx  3 | c    |   1 | xxx  1 | a    |   3 | yyy  2 |
b   |   3 | yyy  3 | c    |   3 | yyy  1 | a    |   5 | zzz  2 | b    |   5 | zzz  3 | c    |   5 | zzz
 
(9 rows)

Is there any "proper", standard ordering that I can assume for sure ?
Maybe PostgreSQL 8.4/9.0 versions have strict ordering and older
versions are using mixed ordering depends on something I don't know (I
am just guessing).

Thanks in advance.

Regards,
G. Sz.