PageViewController minimal

gistfile1.swift

import UIKit

class ViewController: UIPageViewController, UIPageViewControllerDataSource {
  var pages = [UIViewController]()
  
  override func viewDidLoad() {
    super.viewDidLoad()
    self.dataSource = self
    
    pages = [
        self.storyboard?.instantiateViewControllerWithIdentifier("vc1") as! UIViewController
      , self.storyboard?.instantiateViewControllerWithIdentifier("vc2") as! UIViewController
      , self.storyboard?.instantiateViewControllerWithIdentifier("vc3") as! UIViewController
    ]
    self.setViewControllers([pages.first!], direction: .Forward, animated: false, completion: nil)
  }
  
  func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
    return ( pages.first == viewController ) ? nil : pages[ find(pages, viewController)!-1 ]
  }
  
  func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
    return ( pages.last == viewController ) ? nil : pages[ find(pages, viewController)!+1 ]
  }
  
}

Reminder to self. This is a really bad idea. Memory 'n all that