- (void)updateBoard {
    self.allowInteract = NO;
    [UIView animateWithDuration:0.3
                     animations:^{
                         for (int i = 0, j = 0; i < self.boardView.subviews.count; i++) {
                             CardView *view = self.boardView.subviews[i];
                             if ([self.cardViewsToRemove containsObject:view]) {
                                 view.center = [self centerBoundaryPositionOfView:view];
                                 continue;
                             }
                             NSUInteger row = j / self.grid.columnCount;
                             NSUInteger column = j % self.grid.columnCount;
                             CGRect frame = [self.grid frameOfCellAtRow:row inColumn:column];
                             view.frame = frame;
                             j++;
                         }
                     }
                     completion:^(BOOL finished) {
                         for (UIView *view in self.cardViewsToRemove) {
                             [view removeFromSuperview];
                         }
                         [self.cardViewsToRemove removeAllObjects];
                         self.pinched = NO;
                         self.allowInteract = YES;
                     }];
}