Cannot find this artist's name!!!! help!?

Question:Okay, so i got this paper in my art class and i have to find the names or remember them from when we learned about the person. I've got almost all of the names but this one artist is impossible to find!!! So my only clues are that: it's a woman, she is british, she is an optical illusionist, from the 60's to 70's era of art, she has 13 letters in her name (first and last), and it ends with a "t". So please, please, please someone help me!!! All I remember from the stuff Ms. Cozzinni (my art teacher, ttly awesome) told us was that she mainly does black and whites. I remembered her name YESTERDAY. Now it's gone. and I really need that name. thanks for your help!

Best Answer - Chosen by Asker: Okay, so i got this paper in my art class and i have to find the names or remember them from when we learned about the person. I've got almost all of the names but this one artist is impossible to find!!! So my only clues are that: it's a woman, she is british, she is an optical illusionist, from the 60's to 70's era of art, she has 13 letters in her name (first and last), and it ends with a "t". So please, please, please someone help me!!! All I remember from the stuff Ms. Cozzinni (my art teacher, ttly awesome) told us was that she mainly does black and whites. I remembered her name YESTERDAY. Now it's gone. and I really need that name. thanks for your help!

http://en.wikipedia.org/wiki/Bridget_Ril...
http://en.wikipedia.org/wiki/Op_art