Make is related to Rub. Brush is a type of Rub. 
Mask is a type of Cover. Cover is related to Grass. you are likely to find Grass in/at/on Lawn. you are likely to find Shit in/at/on Lawn. 
Make <--RelatedTo--> Rub <--IsA-- Brush 
Mask --IsA--> Cover <--RelatedTo--> Grass --AtLocation--> Lawn <--AtLocation-- Shit 