##
> my $Colors = zeroes(long,256,256,256);
##
##
> 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