In this quote, Max has both "cool cement" and "plenty of time." These two things are put together in an odd way because they are not usually seen together. Zeugma is supposed to make the reader confused as to what the character, or the author, is trying to say. But that is the effect that it is supposed to have on the reader. The author used this to show us how much time that Max has and how much, or how little, he has to spend it on. This allows us to see the struggle that Max is going through living in his conditions and the boredom it brings, along with creativity.