davet@oakhill.UUCP (Dave Trissel) (09/06/85)
> > I expect (if the owners would allow you to do it), simply measuring the > platform with a tape measure and (perhaps) a carpenter's level would > expose the trickery. It is probably "off level" by a couple of degrees, > and one side is a little longer than the other to make it appear level > to the eye. > This is probably true, but the effect is quite astonishing since it appears that much more than a few degrees difference must exist. I think the combination of a few degrees reinforced with the disorientation produced by the surrounding objects projects the full illusion. After years deciding not to waste the money I finally had so much time to kill one day in Gatlinburg TN I went to the Mystery Hill (or whatever it was.) This was the very first illusion. The guy first put a carpenter's level bwtween the two cement blocks and sure enough it read level. The people changing places showed dramatic differences in height (the two were not the same height normally.) The rest of the tour was full of obvious illusions of water running uphill etc., all due to the off-vertical build of the structures. I was itching to somehow get back to the blocks and check things out but they wouldn't let me and I wasn't about to pay another $2 to go again. The only thing I remember is that the illusion occured on a very steep part of the hill with our group seeming to be on a lower horizontal plane than the setup. One would think that the trees would be a dead giveaway to real vertical but somehow they weren't. Smaller trees around the "house" were obviously artificially placed (and thus angled off vertical of course.) I tried to get a line-of-sight with the angled trees and natural very large ones at a distance, but the sharp curve of the hill and brush made it very difficult to do. Finally I found one spot where I could see enough of the tops of some distant trees to get a vertical reading and then the artificial tilt of the smaller trees and building were quite obvious. Of course, the carpenter's level may have been bogus, or it was placed just at the only points which would show a true level. Anyway it was a very interesting effect. -- Dave Trissel {ihnp4,seismo}!ut-sally!oakhill