Cartridge code (269 chars):

e=rnd(1)
::★::
cls(7)
srand(e)
for f=0,80 do
x=rnd(127)
y=rnd(127)
s=rnd(5)
m=2+rnd(5)
for i=-s,s,.5 do
 line(x+i,y,x-s*m+abs(i*m),y-abs(i/2)-s/2,12)
end
for i=-s,s,.5 do
 c=10
 if(i>0)c=11
 line(x+i,y,x+i,y-s*m+abs(i*m),c)
end
line(x-s/2,y,x+s/2,y,4)
end
flip()
goto ★