Turtle monad and monad transformer.
The Turtle monad embodies the LOGO style of imperative
drawing - sending commands to update the a cursor.
While Wumpus generally aims for a more compositional,
"coordinate-free" style of drawing, some types of
diagram are very easily expressed in the LOGO style.
|No longer sure about this combinator...
|Produced by Haddock version 2.6.1|