# 3.9 Summary

At this point, we have covered enough of Scheme to write useful programs (even if the programs we have seen so far seem rather dull). In fact (as we show in Chapter 12), we have covered enough to express every possible computation! We just need to combine these constructs in more complex ways to perform more interesting computations. The next chapter (and much of the rest of this book), focuses on ways to combine the constructs for making procedures, making decisions, and applying procedures in more powerful ways.