use strict; 
use warnings;
$_=[(25.5*6<<q{9}.1)=~m+(..)+go],//moss;
--$.for(1..((5<6).0));($/=>$.)=(-$.,$.);
$.*=@{_}=map{$.+=$/;$_+$.}grep{$_%2}@$_;
push@_,map{if(!int){$.+=$.}else{$.+=$/};
$_+$.}grep{($_+1)%2}@$_;die map{chr}@{_}
[eval join(q{,},2,1,4,3,0)]=>$/||\$\<<1;

##</code><code>##

use strict; 
use warnings;
$_ =  [(25.5*6<<q{9}.1) # 25.5*6 = 153; q{9}.1 = '91'; 153<<91=3355443200
        =~ m+(..)+go    # [ 33, 55, 44, 32, 00 ] ('o' was just for 'go')
      ],//moss;         # amazing what you can add with no effect: here,
                        # m// with useless options, matching (nothing) against $_

# 3355443200 is the key: each pair of digits is some multiple of 10 away from my target letters

--$.for(1..((5<6).0));  # fun way for $.=-10;
($/=>$.)=(-$.,$.);      # $/=10; and for confusion, $.=$.

$.*=@{_}=map{           # 4) scalar@{[33,55]}=2, so $.=10*2;
             $.+=$/;    # 2) $. = $. + $/; (-10+10=0; then 0+10=10)
             $_+$.      # 3) 33+0=33; 55+10=65
         }
         grep{$_%2}@$_; # 1) get the odd numbers from $_:  33, 55

# At this point:  @_ = [ 33, 65 ];

push @_, map{
             if(!int){       # 2) if(00)
                $.+=$.       #       $.=$.+$., or $.=40+40
             }else{          # 3) else (44 or 32)
                $.+=$/       #       $.=$.+$/; (20+10; then 30+10)
             };
             $_+$.           # 4) return 44+30; then 32+40; then 00+80
         }
         grep{($_+1)%2}@$_;  # 1) get the even numbers from $_: 44, 32, 00

# Now: @_ = [ 33, 65, 74, 72, 80 ]

die                  # 3) die("JAPH!\n")
         map{
             chr     # 2) chr(74),chr(65),chr(80),chr(72),chr(33)
                     #     plus chr(10) from =>$/
         }
         @{_}[eval join(q{,},2,1,4,3,0)]  # 1) fancy for @_[2,1,4,3,0]
         =>$/        # this is still 10
         ||\$\<<1;   # this can all be ignored, since $/ is true