Section 2.2.1 Representing sequences [i.e., finally introducing lists, and a butt-ton of built-ins/primitives]
Exercise 2.18 - implementing (reverse) myself. Which way is the most Scheming??
Exercise 2.19: a minor modification to (count-change) from section 1.2.2. What, do they just want to force you to read that section?
I swear, stop introducing language features in exercises...