Who doesn't remember Turtle graphics?

Hacked this quickly to make a nice background image of the Hilbert curve using the Lindenmayer system:

// Hilbert curve
rules := strings.NewReplacer(
	"A", "-BF+AFA+FB-",
	"B", "+AF-BFB-FA+")
axiom := "A"
level := 6

The code above produces a nice image like this:

Here some more examples:

// Koch curve
rules := strings.NewReplacer(
	"F", "F+F-F-F+F")
axiom := "F"
level := 4

// Dragon curve
rules := strings.NewReplacer(
	"X", "X+YF+",
	"Y", "-FX-Y")
axiom := "FX"
level := 12