Simple is a different concept from Complicated. World can be Complicated. World is a type of Part. 
Form is related to Language. Language is related to Format. Format is a synonym of Arrange. Stack is a type of Arrange. 
Simple <--DistinctFrom--> Complicated <--HasProperty-- World --IsA--> Part 
Form <--RelatedTo--> Language <--RelatedTo--> Format <--Synonym--> Arrange <--IsA-- Stack 