The Greeks proposed the existence of five basic elements. Of these, four were the physical elements – Fire, Air, Water and Earth – of which the entire world is composed. Alchemists eventually associated four triangular symbols to represent these elements.
– Elemental-Symbols, Catherine Beyey, About.com, Altreligion.about.cm (http://altreligion.about.com/od/westernocculttradition/ig/Elemental-Symbols/)
EARTH: A downward-pointing triangle with a horizontal
line through it, a triangle pointing down and with a horizontal line through the middle of it.
WATER: A downward-pointing triangle, a triangle pointing down.
AIR: An upward-pointing triangle with a horizontal line through it, A triangle pointing up and with a horizontal line through the middle of it,
FIRE: An upward-pointing triangle,.a triangle pointing up.
The Four Elements / Earth, Water, Air, Fire 