The example concluding the chapter demonstrates what we've learned so far. We can write complex logic by chaining the Observable instances using a variety of operators. We can transform incoming data using the map() or flatMap() operators and can branch logic by using the groupBy() or filter() operators or the different flatMap() operators. We can join these branches again with the flatMap() operators. We can select parts of the data with the help of different filters and accumulate it with the scan() operator. Using all of these operators, we can write pretty decent programs in a readable and simple way. The complexity of the program doesn't affect the complexity of the code.

The next step is to learn how to combine the branches of our logic in a more straightforward fashion. We'll learn how to combine data coming from different sources too. So let's proceed with the next chapter!