The Celtic symbol for father daughter tells the story of Brighid who sat close to her dying father. As she waited she weaved a knot from rushes. Her father noticed and asked her what she was doing. She explained how each loop although individual is not able to be separated from the whole just as their relationship was interwoven so too were they wrapped up with those who would follow in the life after.
celtic knots, which can be decorative elements, or you can even try writing within them, using the knot as your guidelines. This works best with a lettering style like Uncial or Romans, without ascenders or descenders.