A folding tree with three sets of recursive branches.

When rotated enough they form a Sierpiński triangle!

Cartridge code (209 chars):

function r(x,y,d,a,b,c)local e,f=x+cos(a)*d,y+sin(a)*d
line(x,y,e,f,15-c)
for j=-b,b,b do
if(c>6)break
r(e,f,d/2,a+j,b,c+1)end
end
camera(-64,0)::★::cls()
s=64
r(0,64+s,s,.25,.225-sin(t()/5)/9,0)
flip()
goto ★