Limb is related to Foot. Foot is related to Measure. 
Pretty is related to Ugly. Ugly is the opposite of Attractive. Attractive is related to Beauty. Beauty is related to Black. 
Limb <--RelatedTo--> Foot <--RelatedTo--> Measure 
Pretty <--RelatedTo--> Ugly <--Antonym--> Attractive <--RelatedTo--> Beauty <--RelatedTo--> Black 