- (IBAction)selStore:(id)sender {
    dImageView = [NSKeyedArchiver archivedDataWithRootObject:ivDemo];
}

- (IBAction)selDelete:(id)sender {
    NSArray *viewsToRemove = [ivDemo subviews];
    for (UIView *v in viewsToRemove) {
        [v removeFromSuperview];
    }
}

- (IBAction)selRestore:(id)sender {
    ivDemo = [NSKeyedUnarchiver unarchiveObjectWithData:dImageView];
    [ivDemo setNeedsDisplay];
}