Poggendorff's illusion ƒ|ƒbƒQƒ“ƒhƒ‹ƒt‚ÌöŽ‹ ライフサイエンス
An optical illusion first described by the German scientist Johan Poggendorff in 1860. He observed that a diagonal line appears disjointed when it is intersected by two parallel lines.