This seems to be allowed

Code:
Struct tdChicken
     String sName
     tdChicken tChicken
End_Struct
But how can I do this

Code:
Struct tdEgg
     tdChicken tChicken
End_Struct

Struct tdChicken
     String sName
     tdChicken tChicken
     tdEgg tEgg
End_Struct
Why ?

This itemActivity
https://docs.microsoft.com/en-us/gra...graph-rest-1.0

Contains listItem
https://docs.microsoft.com/en-us/gra...graph-rest-1.0

Which contains itemActivity