zen doodle letters- negative space *NOTE* this is a GREAT site for zentangles, how-to's, and great examples. For diy, look up zentangle patterns and trace around whatever letter. Great for framing and embroidery!
Edna Andrade was an American abstract artist & an early Op Artist. Renowned for her challenging optical and hard-edged abstract paintings, the artist had a significant influence on the Philadelphia art scene for over forty years. The artist’
Vásárhelyi Győző, known as Victor Vasarely was an artist who is often regarded as the father of Op Art. He began to study medicine in Hungary, but left the race after two years. Wikipedia--Slide sequence alt to willowisp -conc.