Stupid is a synonym of Dense. Dense is a synonym of Difficult. Difficult is related to Complicated. 
Depth is a type of Degree. Degree is related to Calculation. Calculation is a type of Planning. 
Stupid <--Synonym--> Dense <--Synonym--> Difficult <--RelatedTo--> Complicated 
Depth --IsA--> Degree <--RelatedTo--> Calculation --IsA--> Planning 