Zone of proximal development: The term is given by a psychologist named Lev Vygotsky. The term zone of proximal development (ZPD), is defined as the difference in a person's pattern of learning or doing something on his or her own and that with the help of others.
Example: A student can perform a mathematics calculation with the help of a teacher but can not perform when he or she is alone.
In the question above, according to Lev Vygotsky, putting together these puzzles falls in Stephan’s zone of proximal development.
