my $dc = $frame->{dc} = Wx::MemoryDC->new();
	my $bmp = $frame->{bmp} = Wx::Bitmap->new( $maltafelgroesse, $maltafelgroesse );
	$dc->SelectObject( $bmp );
	leere_zeichenbrett();
	my $maltafel = $frame->{tafel} = Wx::StaticBitmap->new( $panel, -1, $bmp);
        $dc->Clear();
	$dc->SelectObject( $bmp );
        $dc->SetTextForeground( Wx::Colour->new( 0,0,128) );
        $dc->DrawText( $ziffer, $x, $y );