Sentence:  Evil places where the wind whistles and the dust grates, places that are <WSD>blotches</WSD> of shadow, <WSD>blotches</WSD> of rust, <WSD>blotches</WSD> of oil: innumerable <WSD>blotches</WSD>. 
Meaning of the word marked with <WSD> tags:  An irregularly shaped area.