sorry for my bad english
that's familiar to me... i'm french.

BTW, your picture helps a lot to figure out what you want to do.

Have a counter variable, and check for your three sensor signal comming...

Code:
MyCounter     VAR     BYTE
MyCounter=0


' Add this line to the SELECT CASE stuff
          CASE 7 'when all 3 sensor tripped
               IF MyCounter<3 then
                   MyCounter = MyCounter + 1
               ELSE
                   Gosub LetsTurn90Degree
               ENDIF