The unity candle is lit by the bride and groom from two separate family candles, representing the union of your families and the fact that you and your fiance are creating a family of your own. Often your mothers light the family candles, and then you two each hold your family's candle to light the unity candle together (it may be a larger candle, or a different color, and it's placed in the center, with the family candles off to your respective families' sides).
but.... how about this instead..
plant a tree
or... maybe this...
intertwine ropes
mixing the sand
okay let's try it with wine..
