AP Computer Science Principles - Unit 4 Word Wall - for Code.org AP CSP---Increase your students' vocabulary retention and understanding by creating a Word Wall in your classroom! Word Walls have been proven to aid in students' word identification, recall in use, connections between concepts, and contextual understanding within a unit or course. Create a language-rich classroom environment where students feel confident in discussions and do better on the AP Exam. Unit 4: Variables, Conditionals,