This article asks the following: How does a teacher use a metaphor in relation to a
prototypical image to help students remember a set of theorems? This question is analyzed
through the case of a geometry teacher. The analysis uses Duval's work on the
apprehension of diagrams to investigate how the teacher used a metaphor to remind
students about the heuristics involved when applying a set of theorems during a problem-
based lesson. The findings show that the teacher used the metaphor to help students recall …