[ª] , [©] , [^] , [¨]Tracks of incenterEexcenter / Excenter are three.(GC World : Various Problems ,Something strange?)
There is a circle O and three corners of ĢABC are on the circle.
Three excenters are named I1, I2, and I3 respectively.
Please find the tracks of I1, I2, I3, when point A moves on the circle.

GC/Win


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