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From the point of view of mathematics it is considered a geometric shape due to a plot consists of two nodes - you get intertwined in a way to simplify a cloverleaf junction and a simple closed curve. The geometric shape is obtained by submitting the said plot in a figure substantially symmetrical, invariant to rotations of 120 degrees.
In heraldry is synonymous Trinacria or Triscele. The triquetra has the same topology called the Gordian knot.
A very common representation of the symbol is a circle passing through three rings of interconnected Triquetra. The circle emphasizes the unity of any combination of three elements.