28:13 · This is a medieval ideogram representing the four elements. Compare with the sign entry below, of which it is the central part.
    This symbol has been used to represent the elements in astrology, alchemy, and philosophy. At the top are the triangles representing the elements of air and fire, and at the bottom are the triangles for the elements earth and water.
    The same structure, but with the inner square filled, appears on some electronic machines.
    See and , and the Word Index for other element symbols.