Sorry to keep pointing things out, but I keep rereading this book because it is so informative, and I find something every now and then.

I just noticed that on page 629, the answer for Exercise 4 in Chapter 4 is a solution that repeats Exercise 3 using an array of arrays, but the text on page 96 says to repeat Exercise 2 using an array of arrays. It really means to repeat Exercise 3, which definitely makes more sense.