...It does this by providing a range of new grammar classes that can be added to the plot object in order to customize how it should change with time. Here we take a simple boxplot of fuel consumption as a function of cylinders and let it transition between the number of gears available in the cars. As this is a discrete split (gear being best described as an ordered factor) we use transition_states and provide a relative length to use for transition and state view. As not all combinations of data are present there are states missing a box. We define that when a box appears it should fade into view, whereas it should shrink away when it disappears. ...