{ width="320" }
{ width="320" }
From a blob in one corner to a ring, on the 16×16 grid graph, by
shooting. The mass spreads as it travels, then settles into the ring (display
smoothed between nodes).
Barycenters of digits
{ width="420" }
{ width="420" }
The corners are four 16×16 digit images, densities on the pixel grid.
Every other panel is their barycenter, for weights bilinear in the panel's
position, by the SOCP. The digits are centered on top of one another, so mass only
moves locally, and the in-between panels look more like a cross-fade than a
slide.
Three methods, one transport


The blob-to-ring geodesic at time ½, one square per node: shooting
and the SOCP agree; Sinkhorn's entropic interpolation blurs.
Gradient descent on a density


Minimizing the transport distance to a target with Adam; see
differentiable geodesics.