Sentence:  Automatism in art can arise quite deliberately from manual techniques (such as "frottage", <WSD>"grattage</WSD>" and "decalcomania" in the visual arts, algorithmic or statistical procedures in musical composition, or random verbal collages in poetry) or accidentally from altered states of consciousness (for example, intoxication, hallucination, trance and ecstasy). 
Meaning of the word marked with <WSD> tags:  A technique popularized by (Max Ernst) involving scraping at dried (paint) in order to form patterns.