Hi tamaguchi, try like this,

use strict;
use warnings;
use Tk;

my $top = MainWindow->new();
my $canvas = $top->Canvas(width=>300, height=>245, background=>'blue')
+->pack();

my $origin_x=110;
my $origin_y=70;
my $PI=3.141592635;
my $circle_radius=5;
my $path_radius=0;

for (my $angle=0; $angle<=180; $path_radius+=7, $circle_radius+=3, $an
+gle+=10)
{
    my $path_x=$origin_x+$path_radius*cos($angle*$PI/90);
    
    my $path_y=$origin_y-$path_radius*sin($angle*$PI/90);
    
    $canvas->createOval($path_x-$circle_radius,
                    $path_y-$circle_radius,
                    $path_x+$circle_radius,
                    $path_y+$circle_radius,
                    -fill=>'yellow');
            
    $canvas->update();
    
    sleep(1);
}
            
MainLoop();
[download]

I got this code in perlmonks only.