sub hole{grep$_=$_&&chr hex,split/(..)/,pop}  # 34

  sub hole{$_=pop;s/../chr hex$&/ge;/./g}       # 29

  sub hole{map{chr hex}pop=~/../g}              # 32

  sub hole{split//,pack'H*',@_}                 # 19

  sub hole{(pack'H*',@_)=~/./g}                 # 19

  sub hole{$_=pack'H*',@_;/./g}                 # 19