To emit notes in pairs in a interval for recorder practice.

music_practice.p6

my Bool $highs_only = False;
my Bool $lows_only  = True;
my Str  @notes;
if $highs_only {
    @notes = <C C# D Eb E F F# G G# A Bb B>;
} elsif $lows_only {
    @notes = <Low-C Low-C# Low-D Low-Eb Low-E Low-F Low-F# Low-G Low-G# Low-A Low-Bb Low-B>;
} else {
    @notes = <C C# D Eb E F F# G G# A Bb B Low-C Low-C# Low-D Low-Eb Low-E Low-F Low-F# Low-G Low-G# Low-A Low-Bb Low-B>;
}                                                                                     
                                                                                      
my     $seconds = 4; #Number of seconds you want between each pair of notes is displayed.
my Int $pair    = 1; #Number of notes you want to pair at one time.                   
                                                                                      
for 0 .. Inf {                                                                        
    sleep( $seconds * 1 );                                                            
    print  "\e[H";                                                                    
    print  "\e[J";                                                                    
    for 1 .. $pair {                                                                  
        print @notes.pick ~ '   ';                                                    
    }                                                                                 
}