A fractal which can be written as a Lindenmayer system with initial string "YF", string
rewriting rules "X" -> "YF+XF+Y", "Y" ->
"XF-YF-X", and angle 
.
Sierpiński Arrowhead Curve
See also
Dragon Curve, Hilbert Curve, Koch Snowflake, Lindenmayer System, Peano Curve, Peano-Gosper Curve, Sierpiński Curve, Sierpiński SieveExplore with Wolfram|Alpha
References
Dickau, R. M. "Two-Dimensional L-Systems." http://mathforum.org/advanced/robertd/lsys2d.html.Mandelbrot, B. B. The Fractal Geometry of Nature. New York: W. H. Freeman, p. 142, 1983.Referenced on Wolfram|Alpha
Sierpiński Arrowhead CurveCite this as:
Weisstein, Eric W. "Sierpiński Arrowhead Curve." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/SierpinskiArrowheadCurve.html