While there is a vast literature on feedback, it is unclear how much traditional prescriptions for feedback apply during creative projects, since creativity often relies on nonlinear and ambiguous work patterns. We conducted an inductive study of feedback meetings in creative projects in two contexts — modern dance and product design — to understand how feedback might influence the development of creative prototypes. Our emergent findings contribute to theory by revealing the interactive nature of feedback - that feedback providers and creative workers co-construct an problem space that provides openings for changing prototypes. Our analysis revealed sets of moves that feedback providers (personalizing, puzzling, measuring, and prescribing) and creative workers (backgrounding, forecasting, and opening) use to interact. We also found evidence that patterns among these moves helped guide one of two responses moves: excavations, when feedback spurs comprehensive changes by prompting creative workers to return to old ideas, and adjustments, when feedback spurs incremental refinements to the prototype. We integrate these findings into a process model that describes how feedback influences creative projects over time.