use Bui;

my $html = do{ local $/; <DATA> };
my $Isize :shared = 100;
my $Osize :shared = 20;
my $step  : shared = 0;
my $img   :shared;

Bui->init( $html, \$Isize, \$Osize, \$step, \$img );

my $gd = GD->new( ... );

while( 1 ) {
    my @in = gendata( $Isize );
    plotPoints( $gd, @in );
    $img = $gd->png;
    while( @in > $Osize ) {
        my $discard = selectDiscard( @in );
        splice @in, $discard, 1;

        if( $step ) { ## If the "Replot at each step?" checkbox is checked

             ## clear old plot
             $gd->drawRect( 0,0, $x, $y, white ); 

             ## Plot points minus the discarded one
             plotpoints( @in ); 

             ## Update the image; the next time the browser polls for an update
             ## the revised image will be sent to the browser and be displayed
             $img = $gd->png; 
        } 
    }   
    ## clear old plot
    $gd->drawRect( 0,0, $x, $y, white ); 

    ## Plot points minus the discarded one
    plotpoints( @in ); 

    ## Update the image; the next time the browser polls for an update
    ## the revised image will be sent to the browser and be displayed
    $img = $gd->png; 
}