Here's my picture of orthogonal zippers passing through each other:

There it is; 1.3 megs of pixels...

Actually, I redid it so it's only .3 megs of pixels... But there are some defects in the picture now, because I didn't edit it carefully enough. Oh well -- at least it loads faster now.



Here's the Mathematica code I used to generate it.  It's not very efficient, and took over half an hour to run.
Slice[x_,y_,t_]:=Table[{t,Sin[a]+x,Cos[a]+y},{a,Pi/17,2Pi,Pi/17}]
Banana[fx_,fy_]:=Glue/@Partition[Table[Slice[fx[t],fy[t],t],{t,0,10,.2}],2,1]
Glue[{rind1_,rind2_}]:=
  Polygon/@Transpose[{rind1,RotateRight@rind1,RotateRight@rind2,rind2}]
SlowStep[c_][x_]:=Which[x<c,0,x>c+Pi/2,1,True,Sin[x-c]^2]
SlowStep[c_,f_,p_][x_]:=Which[x<c,0,x>c+Pi/2,1,True,Sin[x-c]^2]f+p
slowmo[t_]:=ArcTan[(7.-t)/4]10/Pi+t
Do[With[{t=slowmo[v]},Show[Graphics3D[
           {Banana[SlowStep[12-t,1,0],SlowStep[t-2,1,-1]],
            Banana[SlowStep[12-t,-1,0],SlowStep[t-2,-1,1]],
            Banana[SlowStep[12-t,-1,0],SlowStep[t-2,1,-1]],
            Banana[SlowStep[12-t,1,0],SlowStep[t-2,-1,1]]}],
           Boxed->False,PlotRange->{{0,10},{-2,2},{-2,2}}]],
   {v,-3.5,17.5,.5}]//Timing
I then copied and pasted each of the frames into Microsoft Gif Animator, in reverse order (to compensate for a brain-dead bug in said animator), and presto, here it is.
 
-Matthew Cook
matthewc@caltech.edu