Since the end of the last century, I have occasionally repeated five or six straightforward exercises in classrooms in different countries with students of different cultures, ages, and social classes―with the same result.
One (inspired in Africa) refers to the classification of geometric figures, where we always see the differences and never what they have in common. In another, in the United States, I draw a cube on the blackboard and, when asked what they see, they unanimously say that it is a cube. It is not a cube, but three rhombuses together. To the question of what colors the sky and the sun are, the answers have also been unanimous, for years. But the repetitive response is a question: “Professor, are you also going to tell us that the sky is not blue and the sun is not yellow?” After all, that’s how they are on flags, in children’s drawings, and in any other…
