Corner Piece (Cayuga Salt Mine Project) コーナー・ピース（カユーガ岩塩坑プロジェクト）

Smithson is best known for his "Spiral Jetty"(1970), a piece of Land Art in which he built with rocks and earth a jetty in the shape of a spiral in a lake. Before he started creating large-scale outdoor works, he worked on a conceptual project named "Site/Nonsite" that bridged outdoors (perception) and indoors (abstraction). One of its realizations, the Cayuga Salt Mine Project, of which this work is a part, had a particularly extensive concept, and was also very carefully implemented. It is in this Project that Smithson first introduced "mirror displacement," and using this technique, he contrasted the mirrors and the artificial rectangles they create against the natural irregular forms of rocks and mineral veins, and in this way formed a relationship between them. Of works employing mirrors, the corner piece produces a particularly impressive effect as the mirrors create an illusional space that stretches in three directions. As is embodied by the concept of "Site/Nonsite," Smithson held strong interest in the relationship between the outdoors and the indoors, and created indoor works (nonsites) which were more than models to explain his outdoor projects. For these works, he is recognized as a very important figure in the field of sculpture too as an artist who practiced Minimal Art in his own modified form.