fireflybob,
As things stand at the moment it is perfectly legal to fly an racetrack circuit if the traffic conditions permit and you can obey the Rules of the Air with respect to conforming to the pattern, etc.
Might depend on where you fly, in FAA-Land the AIM has pictures of traffic patterns and they have definite base and crosswind legs
AIM 4-3-3. I've heard a story about a plane in the pattern hitting somebody flying a straight in approach. As the person in the pattern who was having fun in a Pitts didn't fly a definite base leg the FAA blamed him. Also, if you don't fly a definite crosswind or base leg on your FAA checkride, the examiner is supposed to fail you.