Sentence:  And because of the jumbled layout of the city—old prefabs mingling with equally utilitarian new construction and makeshift hovels <WSD>jimjammed</WSD> in every which way—an agile person who could jump as well as she could would be able to travel a good distance going from roof to roof. 
Meaning of the word marked with <WSD> tags:  To cram together in a jumbled fashion.