#! /bin/sh
pnmenlarge 13 |
  (exec 3<&0; (echo P3; echo 1 1; echo 255; echo 255 255 255) | pnmscale -xsize 534 -ysize 716 | pnmmpaste /dev/fd/3 0 0) |
  pnmmpaste `count from 0 to 534 by 13 | while read x; do echo black-line-v $x 0; done; count from 0 to 716 by 13 | while read y; do echo black-line-h 0 $y; done`