Does anyone know of a few good examples of using Racket's GUI and drawing/canvas library? I took a look at it a few weeks ago, in the hopes of coming up with a portable way to do simple graphics examples, such as turtles and life and drawing character, but it felt like it would take a lot of study to get anything working. (I've done more curses than Tk, and more Tk than Swing, and not much else.)