Draw a Koch curve. See details: Koch curve

var rules = Hash(
    F => 'F+F--F+F',
)
 
var lsys = LSystem(
    width:  800,
    height: 800,
 
    xoff: -210,
    yoff: -90,
 
    len:   8,
    angle: 60,
    color: 'dark green',
)
 
lsys.execute('F--F--F', 4, "koch_snowflake.png", rules)