, 2023

The incircle of triangle $ABC$ is tangent to sides $BC$, $AC$, and $AB$ at points $D$, $E$, and $F$, respectively. Let $A'$ denote the point of the incircle for which circle $(A'BC)$ is tangent to the incircle. Define points $B'$ and $C'$ similarly. Prove that lines $A'D$, $B'E$ and $C'F$ are concurrent.