> my $P2 = $Pixels->clump(2);  # Collapses $Pixels to [3686400,3]
> my $P3 = $P2->mv(0,1);       # Reverses  $Pixels to [3,3686400]

> $Colors->indexND($P3)++;     # Thread over $P3 2nd dimension, index into $Colors, and increment
> print $Colors->at(0,0,0);    # Print count of black pixels

1