Black and White Optical Illsuion. The black and white keep spinning around and around in this image. We don't know exactly what makes this image work, except for the contrasting white and black colors.
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.