Essentially the same as Merlyn's, but I like this method of dealing with the undef produced by the each iterator wrapping.

#! perl -slw
use strict;

my %hash; @hash{ 'a' .. 'z' } = 'A' .. 'Z';

for( 1 .. 20 ){
    my @four = map{ 
        each %hash for 1 .. rand( keys %hash ); 
        each %hash || each %hash 
      } 1 .. 4;

    print "@four";
}
__END__
P:\test>373821
o a y u
v i h i
j i o x
o g l g
k a d d
i n m s
i v n l
c d b n
j p z e
b n v h
q r i u
y m s r
h s j k
d u j v
y j h i
w l c w
y v o o
z m n k
p w o h
u v m a
[download]