That's pretty cool actually, though that might be a bit limiting if they ever want to change it to be more complex. There is a program called Plymouth that is most seen in free operating systems like Fedora and Ubuntu to display animated boot splashes. If you have plymouth installed in your Linux system, you can navigate to /usr/share/plymouth/ to see that the animation is a sequence of png images that are displayed at boot using kernel mode settings (KMS) and direct rendering manager (DRM). Pretty neat.