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-88-math-circle-formula
The Famous Mass - Energy Equivalence Formula. Drawn with Inkscape with 2 layers. mass masse masa Mass - Energy Equivalence Formula
Famous Mass Energy Equivalence Formula with Explanation for each symbol. Drawn with Inkscape using layers. mass masse masa Mass - Energy Equivalence Formula 2