I had a fun conversation with my 6yo about recursion (or is it encapsulation?). We were out of green Play-doh so she came up with the idea to pretend blue Play-doh is green and to make a lump of green Play-doh out of the blue. When I suggested we can telescope this she spent the whole day saying sentences like "X made out of <p1> made out of <p2> made out of <p3>....". Was cool to see how tickled she was by the idea.