Hermann Grid Illusion

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Hermann's Illusion

L. Hermann came across this illusion in 1870 while reading a book on sound by John Tyndall. There seemed to be ghostly gray blobs between dark figures arranged in a matrix on a white background. If you look directly at a blob, it will disappear.

References

A. Seckel, The Art of Optical Illusions, Carlton Books, 2002 (#84)

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