questionedithistorytranslationsCurrent version This is the accepted version. added by globalquiz.org Aug. 30, 2012, 9:51 p.m. Which lines are parallel? blue and red onlygreen and red onlygreen, blue and rednoneThis is a well known Zöllner illusion, first described in 1860. It may be caused by this impression of depth. The black lines are parallel, too!globalquiz.orgShare and bring new players to the game!0Very uninterestingToo difficultPoorly writtenIncorrect or questionableCorrect this question0Very interesting!reach: rather globalgeometryillusionsoptical illusionstechnologyVotes Acceptable globalquiz.org