The humorous aspect of the images that adorn the students’ notebooks is evident in a rather intriguing case study found in approximately ten logic manuscripts written in Louvain during the first half of the seventeenth century. These manuscripts feature depictions of a devil's head accompanying the title of a chapter in the logic course, "De fallacia secundum opinionem" (On error according to opinion), a topic derived from Aristotle's First Analytics (II.21, 66b19-67b27).