# INCARNATION
package My::Lesson::Example;

	require Exporter;
	our @ISA = qw( Exporter );
	our @EXPORT = qw( @steps );
	
	my @steps = ( 'three', 'four' );


# ABSTRACTION
package My::Lesson;

	use Module::Load 'autoload';
	# or CPAN Module::Runtime
	
	sub new{
		my $class = shift;
		my %opts = @_;
		
		# here must be some logic to load the appropriate incarnation module.
		# paying attention to the @steps array (?)
		#
		# autoload from Module::Load should be the right tool (not tested)
		# autoload $opts{lesson};
		warn "autoloading $opts{lesson}";
		
		return bless { steps => [ @steps ] }, $class;
	}
	
# USAGE	
package main;

my $lesson = My::Lesson->new( lesson => 'My::Lesson::Example' );