Smithson produced theoretical and critical writing in addition to visual art. In addition to essays his writings included visual-text formats such as the 2D paper work "A Heap of Language", which sought to show how writing might become an artwork. In his essay "Incidents of Mirror-Travel in the Yucatan" Smithson documents a series of temporary sculptures made with mirrors at particular locations around the Yucatan peninsula. Part travelogue, part critical rumination, the article highlights Smithson's concern with the as a cornerstone of his work.