One of my standard ‘hello world’ applications is bouncing a ball around the screen. Here’s a video of the WikiReader version:
The rig at the top is a 3.3 V serial level converter that hooks into the debug connector. The WikiReader boots a small serial loader from the SD card so that I can quickly load apps in from the development machine. The ball starts life as a three colour PNG that is split out into an image and mask. The mask lets you draw images on top of each other without destroying the one underneath.
Next step is to turn the image drawing code into a more generic blit and have a look at the performance.