XKCD clickdrag downloader

#! /bin/zsh

baseURL="http://imgs.xkcd.com/clickdrag/"
northsouth=('n' 's')
eastwest=('e' 'w')
extention=".png"

for ns in $northsouth
    for i in {1..20}; do
        for j in {1..20}; do
            for ew in $eastwest; do
                wget $baseURL$i$ns$j$ew$extention
            done
        done
    done
done