ON SHORT FINAL AT SUX FLY-IN EVENT; LCL CTLR ISSUES ALTERNATE PATTERN CLRNC TO RESOLVE A CONFLICT TO A C172 THAT IS INCORRECTLY EXECUTED; RESULTING IN ANOTHER CONFLICT PRIOR TO LNDG.

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I WAS FLYING VFR TO ZZZ TO PARTICIPATE IN A FLY-IN CELEBRATION. I CHKED ATIS AT 30 NM OUT; CALLED APCH AT 22 NM OUT; AND RECEIVED A SQUAWK WHICH I XMITTED AND PUSHED IDENT. ON THE APCH FREQ; I COULD HEAR LOTS OF TFC FLYING TO ZZZ FROM SEVERAL DIRECTIONS. THE APCH CTLR WAS VERY BUSY; AND I HEARD THEM ASK ACFT FOR 360'S FOR SPACING; GIVE VECTORS TO AVOID CONFLICTS; AND GIVE TA'S. I HEARD SEVERAL PLTS CORRECT THE CTLR WITH THEIR CORRECT N-NUMBER; ACFT TYPE; AND POS. THERE WERE PROBABLY ABOUT 15 ACFT CLOSING ON ZZZ AT THAT TIME. THE APCH CTLR CALLED ME 2 TIMES FOR TA'S AND 2 TIMES TO SAY PREPARE FOR A STRAIGHT-IN FOR RWY 13; WHICH I ACKNOWLEDGED. I WAS BUSY LOOKING FOR VARIOUS ACFT TO SEE AND AVOID. AT 1/2 MI FROM THE RWY; I WAS CONCERNED THAT I HAD NOT BEEN SWITCHED TO THE TWR (I HAD SLOWED TO ABOUT 80 KTS AND WAS DSNDING). JUST AS THE CTLR SAID TO SWITCH TO THE TWR FREQ; I SAW A LIGHT BLUE RV-4 DIRECTLY BELOW ME ABOUT 200 FT. I HEARD THE TWR CTLR SAY TO THE RV-4 THAT THERE WAS A CESSNA DIRECTLY ABOVE THEM. I IMMEDIATELY IDENTED MYSELF TO THE CTLR AND OFFERED TO MAKE A 360 DEG TURN. THE CTLR TOLD ME TO MAKE A R DOWNWIND TO RWY 17. IN MY CONFUSION; I IMMEDIATELY TURNED TO THE R AND ENTERED A DOWNWIND; WHICH I REALIZED LATER WAS THE WRONG DIRECTION (I SHOULD HAVE TURNED L). I PROCEEDED DOWNWIND; BASE; AND FINAL TO RWY 35. ON FINAL; I REALIZED I HAD TURNED THE WRONG DIRECTION AND WAS LINED UP WITH THE WRONG RWY. THE TWR CTLR WAS VERY BUSY WITH SEVERAL LNDG ACFT ON RWYS 13 AND 17. I SAW A LOW WING ACFT DEPARTING RWY 17 AND TURNING TO HIS L AND OUT OF MY DSCNT PATH. A COUPLE OF SECONDS LATER; THE TWR CTLR CALLED TO ASK IF THAT WAS ME ON FINAL TO RWY 35. I SAID YES; AND THE TWR CLRED ME TO LAND ON RWY 35. THERE WERE NO OTHER ACFT LNDG RWY 17. I LANDED SAFELY; CONTACTED GND CTL; AND TAXIED TO PARKING. THE PROB AROSE BECAUSE OF NUMEROUS ACFT ARRIVING AT THE ARPT AT THE SAME TIME. CONTRIBUTING FACTORS WERE LOOKING FOR VARIOUS ACFT TO SEE AND AVOID; VERY BUSY CTLRS; ACCEPTING A CHANGE OF RWYS WHILE MENTALLY VERY BUSY; TURNING THE WRONG DIRECTION; AND PROCEEDING TO THE WRONG RWY WHILE THE CTLRS WERE TOO BUSY TO NOTICE MY MISTAKE. THE PROB WAS DISCOVERED BY SEE AND AVOID (SEEING THE RV-4 BELOW AND THE DEPARTING LOW WING ON RWY 17); AND COM FOR THE TWR CTLR. CORRECTIVE ACTIONS WERE TO TURN AWAY FROM THE APCH TO RWY 13 TO AVOID THE RV-4; AND LATER TO IDENT MY MISTAKEN APCH TO RWY 35. I SHOULD HAVE BEEN MENTALLY PREPARED TO DIVERT TO RWY 17 FOR EITHER A R DOWNWIND OR OVERFLY THE ARPT FOR A L DOWNWIND.