back in the 80s-90s if a system like raspberry pi was built, perhaps today 
it had its own demo scene, like the amigas, ataris, spectrums etc. but 
because rpi is a linux machine which is quite capable and "generic" it
doesn't. what a shame :( but what if we could create our own demo scene for
this capable machine? draw only to the framebuffer and in lower resolutions
like 320x240 or 640x480 with 256 colors. it would be nice to see demos for 
rpis :)

fortunately there are some simple demos written for the framebuffer of 
rpi. you can get them here:
          
          https://github.com/drmad/rpi-framebuffer
                
or use git with this command to download the repo:

          git clone https://github.com/drmad/rpi-framebuffer
          
to compile them just write:
                
          make
          
if you want to preview the demos, watch a video of them here:

firedemo -  https://www.youtube.com/watch?v=O2NAr2LjTTM
rotozoomer - https://www.youtube.com/watch?v=liOFy33qi1M

if you want to learn more about framebuffer graphics in rpi, read this 
good blog, which has many tutors about the subject.

http://raspberrycompote.blogspot.com/2013/04/
low-level-graphics-on-raspberry-pi-part.html

...and who knows... maybe in some years from now, see demos exclusive for 
the rpi :)