#!/bin/sh
convert -compress none +distort SRT '0,0 1,.56 0' -thumbnail ${1:-66x23} - pgm:- |
perl -e '
<> eq "P2\n" or die "ascii pgm input required\n";
<>; <>;  # ignore depth, dimensions

my @ch = split //, " .:coO@";
while (<>) {
	print $ch[ $_ * @ch >> 8 ] for /\d+/g;
	print $/;
}
'