Parallel Lines
Six long slanting lines, crossed with short strokes, and a question about whether they run side by side.
这个体验还没有翻译，所以文字仍是英文。
玩法
先看，再回答
Six long slanting lines, crossed with short strokes, and a question about whether they run side by side.
- 不到一分钟 · 1 个问题 · 然后是解释
原理 — 建议试过之后再读
Angles that grow
The long lines are exactly parallel. Each short stroke meets its long line at a sharp angle, and a sharp angle tends to be seen as wider than it is; the strokes on neighbouring lines lean opposite ways, so every line is pushed the opposite way from its neighbour and they seem to splay apart and close together.
The astrophysicist Johann Karl Friedrich Zöllner came across the effect in 1860 in a pattern printed on fabric. It is one of a family — Hering’s bowed lines and Poggendorff’s hidden line belong to it too.