5 answers
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They are both right.
http://www.google.com/search?q=windmill&hl=en&tbo=d&source=lnms&tbm=isch&sa=X&ei=Eo-lUKWGLMTRyAGLz4CYCA&ved=0CAQQ_AUoAA&biw=711&bih=453