Sierpinski arrowhead curve

Uses the LSystem() class from Hilbert curve.

var rules = Hash(
    x => 'yF+xF+y',
    y => 'xF-yF-x',
)

var lsys = LSystem(
    width:  550,
    height: 500,

    xoff: -20,
    yoff: -30,

    len:   4,
    turn: -90,
    angle: 60,
    color: 'dark green',
)

lsys.execute('xF', 7, "sierpiński_arrowhead.png", rules)

Output image: Sierpiński arrowhead