There’s a typo in the exercise description:
Control your sketch with the object’s, location
Control your sketch with the object’s location. (no comma)
In addition, the exercise should reference Example 9-8, not Example 9-9. Here is the full corrected text:
Exercise 16-5: Take any Processing sketch you previously created that involves mouse interaction and replace the mouse with color tracking. Create an environment for the camera that is simple and high contrast. For example, point the camera at a black tabletop with a small white object. Control your sketch with the object’s location. The picture shown illustrates the example that controls the “snake” (Example 9-8) with a tracked bottlecap.