Imagine you have to explain the object in the image below to
– a child in a kindergarten group;
– a student of an eighth grade school group;
– a head technician from a engineering factory;
– a female, retired junior school teacher.
4.32. picture: Two cog wheels with peculiar shapes that set
each other in motion. Istituto e Museo di Storia della Scienza, Florence.
(Photo: Tamás Vásárhelyi.)