// Start:
string koch = "F";

// Rule: F -> F+F-F-F+F
Func<string, string> transform = x => x.Replace("F", "F+F-F-F+F");

// Fractal length:
int length = 3;

// Intialize the location and direction of the turtle:
string command = @"home
setxy 10 340
right 90
";

// Recursive definition to generate Logo commands:
command += Enumerable.Range(1, length)
    .Select(k => koch = transform(koch))
    .Last()
    .Replace("F", "forward 15")
    .Replace("+", String.Format("{0}Left 90{1}", Environment.NewLine, Environment.NewLine))
    .Replace("-", String.Format("{0}Right 90{1}", Environment.NewLine, Environment.NewLine));

// Displays the Logo commands:
command.Dump();