Rise
This is basically the same setup as Vanishing Point and :eyes:, conformally mapping an infinite strip into the region between two circles, though in this case the outer circle has infinite radius, and so is a straight line. The conformal map is ( $-i$ times) the Cayley transform:
Cayley[z_] := (z - I)/(z + I);
The circles in the animation are just the images of equally-spaced, parallel lines in the infinite strip. Here's the code for a Manipulate
version of the dark animation (for the actual GIF, I changed {x, -5, 5, .01}
to {x, -50, 50, .01}
, which takes much longer but looks marginally better; see also this comment for the process of exporting to GIF):
With[{d = 1/60.},
Manipulate[
Graphics[
{Table[
{GrayLevel[y + 1],
Polygon[Table[ReIm[-I Cayley[x + I y]], {x, -5, 5, .01}]]},
{y, -1 + d - s, 0, d}]},
PlotRange -> 1.5 {{-4, 4}, {-1, 5}}, ImageSize -> 540,
Background -> Black],
{s, 0, d}]
]