I just realized that, to illustrate Warren Smith's way of proving the Wall of Fire theorem at my August 7 talk, it'd be cool to have a video or GIF showing how the intersection between the 2-skeleton of a moving cubical network and a fixed plane evolves in time. For instance, say the plane is {(x,y,z): x+y+z=0} and the cubical network is the standard one in Z^3 moving at constant speed in the (1,1,1) direction, which one can write as {(x,y,z); x≡t (mod 1) or y≡t (mod 1) or z≡t (mod 1)}. We see a dynamic dissection of the plane in which equilateral triangles grow and turn into hexagons and then turn into shrinking triangles pointing the other way. Can anyone dash off such a video? If I use it in my talk I will of course give credit. Thanks, Jim Propp