From Deborah Moore
I found “That freaky feeling” very interesting (14 March, p 33). Though I did not try any of the tactile illusions on myself, I discovered that you had arranged for readers to get a demonstration of a different kind of illusion.
For a couple of minutes after reading item 7, which is printed in white on a black background, all the pages I looked at appeared to have stripes across them.
Chippenham, Wiltshire, UK
