English: Philipp Otto Runge’s Color Sphere (Die Farbenkugel). The top two images show the surface of the sphere, while the bottom two show horizontal and vertical cross sections. Taken from http://www.uni-mannheim.de/fakul/psycho/irtel/colsys.html. "Ansicht" is "Perspective"; "Durchschnitt" is "Cut-out". Hues labeled R, O, G, Gr, B, V are red, orange, yellow (Gelb), green, blue, violet. Note:There are mathematical issues with this depiction. For instance, if one calls the concentric rings of the bottom right image "chroma" (counting from the center outward) and the horizontal stripes (counting from the bottom to the top) of the bottom right image "lightness", then it is not possible to specify a color whose "chroma" is 2 and whose "lightness" is 9. This means that each color cannot be uniquely identified by a single set of "hue", "lightness" and "chroma" values.