A mathematics teacher educator (MTE) did not teach math problem posing (MPP) before. She related three stories of herself borrowing classes and teaching MPP for teachers to observe. First, the MTE taught using problem posing. Next, she and teachers-the-observers discussed how she set up and enacted MPP tasks, then responded to in-class matters arising. Finally, she used results from her teaching in subsequent professional development sessions or pre-service teachers’ training. Customarily, the MTE observed teachers. In this study, teachers assumed reciprocal roles where MTE taught for teachers to observe. Her way of teaching for observations was a technique in teacher education-- a reciprocal role in “being observed” and “to observe”. Showing MPP led to professional development for the MTE, in-service teachers, and prospective teachers; who learned about using MPP from elementary to high school.