Below is the early source code and corresponding output in Processing 3. At this point, the images had been imported and loaded and the background created in the setup function, which runs only once at the beginning of the program. In the draw function, which runs continuously (or in this case, runs once upon keyboard input), the early code for keyboard movement (arrow keys) is shown. One of the first bugs that appeared was that the sprite had trailing frames, which signified that the background had to be cleared with each run of draw.