Rented C172, departed from Albert Whitted, St. Pete, Florida, for sightseeing.
Having explored the shoreline for a while, returned to the appropriate place for telling ATC that I would like to join the "Pattern" to land. Tower said come on in, traffic ahead of you. Not just the usual traffic, it was two small peculiar aircraft together, at about 45 mph, heading in on 36. So I said to the Tower, I would like to maneuver for spacing from the traffic, and did a very nice 360.
Only trouble, back on the usual approach line for 36, the two little aircraft had vanished! where did they go?
To my surprise, they had completely altered their pattern, and were now on approach to runway 27! So I told the tower that I also now planned to use 27 and follow the traffic, that was approved. All very relaxed, not all that busy.
But even not busy, so important to KEEP A GOOD LOOKOUT! I hadn't heard the tower mention it would be a different runway....
LOOKOUT IS MOST IMPORTANT! and communication can be helpful in knowing where to look.