Peter Smagorinsky compares the well-known ZPD concept (zone of proximal development) with the less-known, longer-looking ZND (zone of next development).  (Originally published Mar 11, 2020)

Source: http://tiny.cc/t6e5kz   

References: "Is Instructional Scaffolding Actually Vygotskian, and Why Should It Matter to Literacy Teachers?" https://ila.onlinelibrary.wiley.com/doi/abs/10.1002/jaal.756 

The Butterflies of Zagorsk: https://en.wikipedia.org/wiki/The_Butterflies_of_Zagorsk