Take time to write in your lab notebook those topics and/or questions that challenged you particularly.
Specifically, recap what you know about structures in Scheme. How are they similar to classes or other mechanisms you know for organizing data in other languages? What do you see as their strengths, weaknesses? (The last question is, of course, entirely contextual: for what tasks are they useful/well-suited, and how could using them "out of context" make them a poor choice for data abstraction?)
Make a point to discuss this entry with a colleague. Challenge each-other to think beyond the knee-jerk response of "WOW! Scheme is the PERFECT PROGRAMMING LANGUAGE!", but instead start thinking critically about the features of a language and how they might be used.
