$_="qwertyuiopasdfghjklzxcvbnm ";  # string
@b=(m{(.{10})(.{9})(.*)});         # @b = (qwertyuiop, asdfghjkl, 'zxc
+vbnm ');  
@b=map{my@a=split//;$_=\@a;}@b;    # this line makes a 2D array

#net effect of above code is to make a 2D array of letters:

# we could avoid the temp array @a by using:
@b = ('qwertyuiop', 'asdfghjkl', 'zxcvbnm ');  
@b = map {[split//]}@b;

# or alternatively we could:
@a = ('qwertyuiop', 'asdfghjkl', 'zxcvbnm '); 
for (@a) {push @b, [split'',$_]}

# we could even:
@b = (
        ['q','w','e','r','t','y','u','i','o','p'],
        ['a','s','d','f','g','h','j','k','l'],
        ['z','x','c','v','b','n','m',' ']
      );

$_="010422222033310333440222222210433333011333022220430222103044333301
+133022222220303333340240221022222043301333330122222030";
my@c=split//;   # @c is simply an array of the values above 0..4
my$a=6;my$b=1;  # init values
for(@c){
    $b--if($_==1);
    $a--if($_==2);
    $a++if($_==3);
    $b++if($_==4);
    # all we are doing is grubbing out the chars from the 2D array
    # based on the index in @c, I don't like this syntax much:
    print @{$b[$b]}[$a]if($_==0);
    # this array addressing syntax is cleaner I think
    print $b[$b][$a] unless $_;
    # you could also do this ->
    print @b->[$b][$a] unless $_;
}
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Maybe you missed the most obvious thing here. The 2d array is a map of my keyboard.

1,2,3 & 4 move around the keyboad. 0 presses a key.