The Pie Chart widget supports small multiples, which can be toggled in the settings. When grouping on more than one field, the widget can show multiple versions of itself in a grid — one for each value of a particular field. For example, you can group on HTTP requests as well as status by using the following query:

groupBy([method, status])

and then display a pie chart of the status distribution for each method, using the Small multiples property:

Figure 211. Pie Chart in Small Multiples