no skirts tilted here, simon. i just have an affinity for old-timey visual tricks as opposed to the digital ones. they look realer and are tangible.
also, as the link you posted states: "Does it matter if you know how it works?"...nope.
Not to tilt your skirts, there, Kevin, but this has a logical explanation: http://www.sandlotscience.com/MysterySpots/Mystery_Spots_1.htm
Unlike my hatred for that tour guide.