MO20 HAD NMAC WITH C172 IN TFC PATTERN. EVASIVE ACTION TAKEN.

Narrative

I WAS RETURNING TO HWD VFR FROM THE NUT TREE. ORIGINAL CALL TO THE TWR WAS ABOUT 10 MI E. TWR TOLD ME TO ENTER L BASE AND RPT; AND WAS OPERATING WITH REVERSED PATTERN; IE; LNDG TO E. CALLED IN AT ABOUT 2.5 MI OUT AND WAS TOLD TO FOLLOW A PIPER PACER THAT WAS IN A 360 DEG TURN ON FINAL TO RWY 10. I SPOTTED TFC AND ACKNOWLEDGED. AT ABOUT 1 MI OUT I SAW MOVEMENT TO THE L. LOOKED OUT TO SEE A CESSNA 172 APCHING FROM L (ON DOWNWIND IN PATTERN). THE OTHER PLT AND I TOOK SIMULTANEOUS EVASIVE ACTION. HE PULLED UP TO R; I DSNDED TO R. TWR NEVER TOLD EITHER OF US ABOUT THE OTHER. I NEVER HEARD TWR TALK TO THE OTHER ACFT. (MY ACFT IS A MOONEY M205; OTHER ACFT CESSNA 172.) I THINK I WAS SHAKEN BY THE CLOSE ENCOUNTER AND AS A RESULT ENDED UP TOO CLOSE TO THE TFC AHEAD. I INITIATED A GAR AND PER INSTRUCTIONS ENTERED A L DOWNWIND. ONCE AGAIN SPACING WAS TOO TIGHT AND THE TWR REQUESTED A GAR TO THE L SIDE OF RWY. JUST PAST THE DEP END; THE TWR DIRECTED ME TO TURN XWIND. I REFUSED BECAUSE TO DO SO WOULD HAVE TURNED ME INTO THE PATH OF ANOTHER CESSNA ENTERING DOWNWIND. THE CTLR SEEMED TO BE UNAWARE OF THE PRESENCE OF THE OTHER ACFT UNTIL I BROUGHT IT TO HIS ATTN. PREVIOUSLY CALLED IN AND WAS ENTERING THE PATTERN AS INSTRUCTED. IT APPEARS THAT THE CTLR LOST AWARENESS OF WHERE THAT CESSNA WAS; JUST AS HE HAD LOST AWARENESS OF THE CESSNA WHICH HAD ALMOST HIT ME EARLIER. THE CTLR WAS COMPLETELY UNAWARE OF THE NMAC WHICH OCCURRED IN HIS PATTERN.