#!/usr/bin/perl -w
use strict;
use List::Util qw[ shuffle ];

my @tracks = 1..100;
my $range = 5;  # No overlap for this number of songs

{
    my @last;
    for (@tracks){
        unshift @last, $_;
        @last = @last[0..4] if @last > 5;
        # Play it!
        print "$_\n";
    }
    my %h;
    do {
        # print "Shuffling...\n";
        @tracks = shuffle @tracks;
        @h{@last,@tracks[0..4]} = (1) x $range * 2;
    } while keys %h < $range * 2;

    # For demo purposes...
    sleep 5;
    redo;
}