Optical Illusion
These rows are perfectly horizontal and are not moving. A mind-bending anomalous motion variation of the Café wall illusion by Akiyoshi Kitaoka.
Source: http://www.psy.ritsumei.ac.jp/akitaoka/motion30e.html
Image transcription: Rows of black and white zigzag patterns forming 2x2 checkerboards on a grey background create an optical illusion of warping and motion.