Bubble is a type of Illusion. Illusion is related to Image. 
you are likely to find Coffee in/at/on Airport. Coffee is related to Morning. Morning is related to Sleep. Sleep is related to Sheep. 
Bubble --IsA--> Illusion <--RelatedTo--> Image 
Airport <--AtLocation-- Coffee <--RelatedTo--> Morning <--RelatedTo--> Sleep <--RelatedTo--> Sheep 