Using animate, the sequence of images generated by OutputPPM looks weird, whats happening?
This is probably an artefact of the way the animate command displays a series of PPM images. What happens is that OutputPPM generates PPM images which are just big enough to contain all the data in your simulation e.g. if you use 7 levels of refinement and one box, OutputPPM will generate images with 128×128 pixels. If you use an adaptive resolution with a maximum level of 6, the size of the resulting image generated by OutputPPM can be anything in 1×1, 2×2, 4×4, 8×8, 16×16, 32×32, 64×64 depending on the maximum number of levels necessary to verify your adaptation criterion. As a result, animate can see a series of PPM images with a variable size, if you look carefully you will see that the weird patterns you see are smaller-size images of your simulation, displayed in the top-left corner of the initial image. What animate should really do is blank out the previous larger image before displaying the smaller image, to make the difference in size clear.