A variety of symbols or iconographic conventions are used to represent Earth, whether in the sense of planet Earth, or the inhabited world, or as a classical element. A circle representing the round world, with the rivers of Garden of Eden separating the four corners of the world, or rotated 45° to suggest the four continents, remains a common pictographic convention to express the notion of "worldwide". The current astronomical symbols for the planet are a circle with an intersecting cross, , and a globus cruciger, . Although the International Astronomical Union (IAU) now discourages the use of planetary symbols, this is an exception, being used in abbreviations such as M🜨 or M♁ for Earth mass.