"In the 1970s, Butterfield made her first horses from plaster, papier-mâché, and mud and sticks. In 1980, she traveled to Israel on a John Simon Guggenheim grant, and worked with steel and other detritus of wars, and determined the material held emotional content. This set her on a course of making horses with found and welded steel, fused aluminum, copper, and wood — materials that also have a history. Butterfield's ""Yellow River,"" c. 1984, is an uncommon example of the artist's work as the subject is in repose with an experimental minimalist aesthetic. Created using scrap metal from a school bus, the painted steel elements seem to combine organically. Butterfield is widely recognized for her materials-oriented approach to sculpture. 
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