This is clipart converted and broken apart that has been released into the public domain because the document says so, and its from NASA, a USA government agency. The publication is called "The Brain in Space:" http://www.nasa.gov/audience/foreducators/topnav/materials/listbytype/The.Brain.in.Space.html nasa space science 58294main_The.Brain.in.Space-page-98-esther-staircase
Sign to mark your stairwell with silhouette of a spiral staircase in art nouveau style, part of a series. stair stairwell staircase Stairwell door sign