While planning for my AP physics rotational dynamics unit, my energy and creativity had begun to dwindle as most of the design of learning experiences had been on my own. After mentioning this frustration to a colleague, he suggested a short project he remembered completing in his high school physics class—building custom mobiles. He said groups of students were asked to design and construct a mobile using materials in the classroom, and then take measurements to verify the static rotational equilibrium of their mobiles. I’d never heard of a project like this before, but my colleague vividly remembers his experience working on his mobiles, which speaks volumes about the impact it had. These memorable experiences are among the main goals of my instruction, so I began designing this activity to create a lasting impact. Every educator has a horizon of knowledge shaped by their expertise, and collaboration between teachers creates spaces where horizons overlap. Our overlapping horizons, in this case, create new knowledge about how best to serve my students.