The document is a collection of links to various websites about Monument Valley, Escher-inspired staircases, and optical illusions in architecture. Specifically, it includes links about the system requirements for Monument Valley on PC, Escher's artwork exploring relativity and impossible objects, games similar to Monument Valley, and architectural structures featuring endless or paradoxical staircases.

1. https://www.pcmag.com/news/can-your-pc-run-the-monument-valley-1-and-2-panoramic-editions
Escher Inspired Staircases

2. http://magazine.art21.org/2010/08/03/the-paradoxical-art-of-inception/#.WM34YRir02I

7. http://www.gamespot.com/forums/playstation-nation-1000002/ios-game-monument-valley-on-ps-vita-31225141/

8. https://au.pinterest.com/pertemu/monument-valley/

9. http://gazettereview.com/2016/03/top-five-games-like-monument-valley/

12. https://www.pcmag.com/news/can-your-pc-run-the-monument-valley-1-and-2-panoramic-editions

15. http://www.andrewlipson.com/escher/relativity.html

16. http://www.icklepix.com/mobile/?tag=escher

17. https://www.architectsjournal.co.uk/in-pictures-drmms-endless-stair-opens-to-the-public/8653111.article

18. https://architectureas.wordpress.com/2013/10/03/a-stair-drmms-endless-stairs-in-tate-modern/

20. http://distractify.com/old-school/2014/06/14/the-24-craziest-staircases-that-i-want-to-climb-right-now-1197735232

21. https://www.mimoa.eu/projects/Germany/Munich/Rewriting%20Stairs/