Electricity can make you see hovering shapes
http://www.sott.net/article/297707-Electricity-can-make-you-see-hovering-shapes
The 2 paragraphs below are duplicated in the article.
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In the 1930s, one scientist found a more reliable, and less bruising, way to produce phosphenes. An electrical engineer by training, he found he could use electromagnetic waves to stimulate the brain. By varying the frequency of the waves by less than ten percent he found he could produce a "great number" of forms.
Eventually, he came up with fifteen different shapes that most people were likely to see. They could be variations on circular shapes, like radials, concentric circles, or spirals. They could also lines arranged in patterns like lattices, waves, and poles. (Personally I think he's being too vague when he gets to the eighth group, which he just classifies as "odd figures.")
http://www.sott.net/article/297707-Electricity-can-make-you-see-hovering-shapes
The 2 paragraphs below are duplicated in the article.
--
In the 1930s, one scientist found a more reliable, and less bruising, way to produce phosphenes. An electrical engineer by training, he found he could use electromagnetic waves to stimulate the brain. By varying the frequency of the waves by less than ten percent he found he could produce a "great number" of forms.
Eventually, he came up with fifteen different shapes that most people were likely to see. They could be variations on circular shapes, like radials, concentric circles, or spirals. They could also lines arranged in patterns like lattices, waves, and poles. (Personally I think he's being too vague when he gets to the eighth group, which he just classifies as "odd figures.")
