Imagine a punching bag equipped with sensors and connected to a smart system. These sensors could detect the force, speed, and accuracy of punches. For instance, harder punches might trigger a more intense part of a song, while slower punches could trigger a calmer section. The smart system could track users' workouts, including the number of punches thrown, the force exerted, and the calories burned. It could provide real-time feedback to users, helping them optimize their workouts and set goals.