When the teacher drew a rectangle shape on the blackboard in an elementary school math class and asked, "Do you know which ones are the vertical and horizontal lines?", all immediately answered that two lines located in horizontal positions vertically are the "vertical lines" and the other two lines located in vertical positions horizontally are the "horizontal lines". It was initially very difficult for me to understand and I almost started hating math because of this experience.

小学生の算数の授業で先生が黒板に長方形を描いて「縦の線と横の線はどれだか皆分かるかな？」と聞いた時、皆は縦向きの横に位置している２つの線を「縦の線」、横向きの縦に位置している２つの線を「横の線」だと即座に答えていて、僕は何故だか理解し辛くて算数が嫌になりかけた事をふと思い出した。