In this chapter, we discussed how to create a custom polar chart where we saw how to extend the base PolarChart class to define our own polar chart. Also, we created a custom series to create a Market Clock using its own custom sprite class. The implementation demonstrated Sencha Charts' important classes, their responsibilities, interactions, and how you can create a custom polar chart. Also, we saw how to customize the legend and respond to its selection and deselection.

In the next chapter, we will see how to create the third type of chart, spacefilling.