gistfile1.m

...
        CGPoint location = [recognizer locationInView:view];
        self.interactionController = [UIPercentDrivenInteractiveTransition new];
        if (location.x <  CGRectGetMidX(view.bounds) && self.navigationController.viewControllers.count > 1) { // left half
            [self.navigationController popViewControllerAnimated:YES];
        } else {
            [self.navigationController pushViewController:myViewController animated:YES];
            
        }
...