In 1979, to each of a wide variety of Fuchsian groups, Rufus Bowen and Caroline Series constructed an associated function on the unit circle. Each Bowen – Series function is expanding, Markov and satisfies Renyi’s condition. The function thus has a unique ergodic invariant measure equivalent to Lebesgue measure. After sketching the necessary background, we will define a Markov function family using a Bowen-Series function associated with a triangle group.