Cartridge code (226 chars):

function r(x,y,a,d,i)
local w,z=sin(a)*d,-cos(a)*d
if(i<500)r(x+w,y+z,a+0.03+sin(t()/5)*0.0015,d*.995,i+1)
c=sget(i%16,1)
for l=0,1,.25 do
circfill(x+w*l,y+z*l,12+sin(i/1000)*8,c)
end
end
::★::
r(168,44,.05,20,1)
flip()
goto ★