use Audio::Aoede;
use PDL;
use PDL::Graphics::Prima::Simple;

my $A = Audio::Aoede->new();

my $p = $A->square_wave->($A->rate,440);

$A->play($p);
my $samples_per_period = $A->rate / 440;
line_plot($p->slice([0,2*$samples_per_period]));
line_plot($A->spectrum($p,4000));