Here is my second enrty (you can enter 4 times). I call it x-raytrace. Its a completely different style (thats a rule too) but still quite cool for 195 bytes. Its meant to be a x-ray of an impossible bone structure
#macro A(f)cylinder{<9*sin(f),6*cos(f*f),6>,<cos(f),sin(f),9>,1,2} #end
union{
blob {A(4)A(5)A(8)A(9)A(0)A(1)A(2)}
pigment{wood}
finish {reflection{,6}}
}
sky_sphere{pigment{wrinkles}}