These are some live examples of what you can do with tortuga.
variables : X, F
constants : +-[]
axiom : X
rules : (X → F-[[X]+X]+F[+FX]-X)
(F → FF)
angle : 22.5°
variables : A, B
constants : +-
axiom : A
rules : (A → A+B++B-A--AA-B+)
(B → -A+BB++B+A--A-B)
angle : 60°
variables : F
constants : +-
axiom : F++F++F
rules : (F → F-F++F-F)
angle : 60°
variables : F
constants : +-
axiom : F-F-F-F
rules : (F → F-F+F+FF-F-F+F)
angle : 90°